Tag Archives: SSL

How Cloudflare is helping domain owners with the upcoming Entrust CA distrust by Chrome and Mozilla

Post Syndicated from Dina Kozlov original https://blog.cloudflare.com/how-cloudflare-is-helping-domain-owners-with-the-upcoming-entrust-ca

Chrome and Mozilla announced that they will stop trusting Entrust’s public TLS certificates issued after November 12, 2024 and December 1, 2024, respectively. This decision stems from concerns related to Entrust’s ability to meet the CA/Browser Forum’s requirements for a publicly trusted certificate authority (CA). To prevent Entrust customers from being impacted by this change, Entrust has announced that they are partnering with SSL.com, a publicly trusted CA, and will be issuing certs from SSL.com’s roots to ensure that they can continue to provide their customers with certificates that are trusted by Chrome and Mozilla. 

We’re excited to announce that we’re going to be adding SSL.com as a certificate authority that Cloudflare customers can use. This means that Cloudflare customers that are currently relying on Entrust as a CA and uploading their certificate manually to Cloudflare will now be able to rely on Cloudflare’s certificate management pipeline for automatic issuance and renewal of SSL.com certificates. 

CA distrust: responsibilities, repercussions, and responses

With great power comes great responsibility
Every publicly trusted certificate authority (CA) is responsible for maintaining a high standard of security and compliance to ensure that the certificates they issue are trustworthy. The security of millions of websites and applications relies on a CA’s commitment to these standards, which are set by the CA/Browser Forum, the governing body that defines the baseline requirements for certificate authorities. These standards include rules regarding certificate issuance, validation, and revocation, all designed to secure the data transferred over the Internet. 

However, as with all complex software systems, it’s inevitable that bugs or issues may arise, leading to the mis-issuance of certificates. Improperly issued certificates pose a significant risk to Internet security, as they can be exploited by malicious actors to impersonate legitimate websites and intercept sensitive data. 

To mitigate such risk, publicly trusted CAs are required to communicate issues as soon as they are discovered, so that domain owners can replace the compromised certificates immediately. Once the issue is communicated, CAs must revoke the mis-issued certificates within 5 days to signal to browsers and clients that the compromised certificate should no longer be trusted. This level of transparency and urgency around the revocation process is essential for minimizing the risk posed by compromised certificates. 

Why Chrome and Mozilla are distrusting Entrust
The decision made by Chrome and Mozilla to distrust Entrust’s public TLS certificates stems from concerns regarding Entrust’s incident response and remediation process. In several instances, Entrust failed to report critical issues and did not revoke certificates in a timely manner. The pattern of delayed action has eroded the browsers’ confidence in Entrust’s ability to act quickly and transparently, which is crucial for maintaining trust as a CA. 

Google and Mozilla cited the ongoing lack of transparency and urgency in addressing mis-issuances as the primary reason for their distrust decision. Google specifically pointed out that over the past 6 years, Entrust has shown a “pattern of compliance failures” and failed to make the “tangible, measurable progress” necessary to restore trust. Mozilla echoed these concerns, emphasizing the importance of holding Entrust accountable to ensure the integrity and security of the public Internet. 

Entrust’s response to the distrust announcement 
In response to the distrust announcement from Chrome and Mozilla, Entrust has taken proactive steps to ensure continuity for their customers. To prevent service disruption, Entrust has announced that they are partnering with SSL.com, a CA that’s trusted by all major browsers, including Chrome and Mozilla, to issue certificates for their customers. By issuing certificates from SSL.com’s roots, Entrust aims to provide a seamless transition for their customers, ensuring that they can continue to obtain certificates that are recognized and trusted by the browsers their users rely on. 

In addition to their partnership with SSL.com, Entrust stated that they are working on a number of improvements, including changes to their organizational structure, revisions to their incident response process and policies, and a push towards automation to ensure compliant certificate issuances. 

How Cloudflare can help Entrust customers 

Now available: SSL.com as a certificate authority for Advanced Certificate Manager and SSL for SaaS certificates
We’re excited to announce that customers using Advanced Certificate Manager will now be able to select SSL.com as a certificate authority for Advanced certificates and Total TLS certificates. Once the certificate is issued, Cloudflare will handle all future renewals on your behalf. 

By default, Cloudflare will issue SSL.com certificates with a 90 day validity period. However, customers using Advanced Certificate Manager will have the option to set a custom validity period (14, 30, or 90 days) for their SSL.com certificates. In addition, Enterprise customers will have the option to obtain 1-year SSL.com certificates. Every SSL.com certificate order will include 1 RSA and 1 ECDSA certificate.

Note: We are gradually rolling this out and customers should see the CA become available to them through the end of September and into October. 

If you’re using Cloudflare as your DNS provider, there are no additional steps for you to take to get the certificate issued. Cloudflare will validate the ownership of the domain on your behalf to get your SSL.com certificate issued and renewed. 

If you’re using an external DNS provider and have wildcard hostnames on your certificates, DNS based validation will need to be used, which means that you’ll need to add TXT DCV tokens at your DNS provider in order to get the certificate issued. With SSL.com, two tokens are returned for every hostname on the certificate. This is because SSL.com uses different tokens for the RSA and ECDSA certificates. To reduce the overhead around certificate management, we recommend setting up DCV Delegation to allow Cloudflare to place domain control validation (DCV) tokens on your behalf. Once DCV Delegation is set up, Cloudflare will automatically issue, renew, and deploy all future certificates for you. 

Advanced Certificates: selecting SSL.com as a CA through the UI or API
Customers can select SSL.com as a CA through the UI or through the Advanced Certificate API endpoint by specifying “ssl_com” in the certificate_authority parameter. 

If you’d like to use SSL.com as a CA for an advanced certificate, you can select “SSL.com” as your CA when creating a new Advanced certificate order. 


If you’d like to use SSL.com as a CA for all of your certificates, we recommend setting your Total TLS CA to SSL.com. This will issue an individual certificate for each of your proxied hostname from the CA. 

Note: Total TLS is a feature that’s only available to customers that are using Cloudflare as their DNS provider. 


SSL for SaaS: selecting SSL.com as a CA through the UI or API
Enterprise customers can select SSL.com as a CA through the custom hostname creation UI or through the Custom Hostnames API endpoint by specifying “ssl_com” in the certificate_authority parameter. 

All custom hostname certificates issued from SSL.com will have a 90 day validity period. If you have wildcard support enabled for custom hostnames, we recommend using DCV Delegation to ensure that all certificate issuances and renewals are automatic.  

Our recommendation if you’re using Entrust as a certificate authority 

Cloudflare customers that use Entrust as their CA are required to manually handle all certificate issuances and renewals. Since Cloudflare does not directly integrate with Entrust, customers have to get their certificates issued directly from the CA and upload them to Cloudflare as custom certificates. Once these certificates come up for renewal, customers have to repeat this manual process and upload the renewed certificates to Cloudflare before the expiration date. 

Manually managing your certificate’s lifecycle is a time-consuming and error prone process. With certificate lifetimes decreasing from 1 year to 90 days, this cycle needs to be repeated more frequently by the domain owner. 

As Entrust transitions to issuing certificates from SSL.com roots, this manual management process will remain unless customers switch to Cloudflare’s managed certificate pipeline. By making this switch, you can continue to receive SSL.com certificates without the hassle of manual management — Cloudflare will handle all issuances and renewals for you!

In early October, we will be reaching out to customers who have uploaded Entrust certificates to Cloudflare to recommend migrating to our managed pipeline for SSL.com certificate issuances, simplifying your certificate management process. 

If you’re ready to make the transition today, simply go to the SSL/TLS tab in your Cloudflare dashboard, click “Order Advanced Certificate”, and select “SSL.com” as your certificate authority. Once your new SSL.com certificate is issued, you can either remove your Entrust certificate or simply let it expire. Cloudflare will seamlessly transition to serving the managed SSL.com certificate before the Entrust certificate expires, ensuring zero downtime during the switch. 

Introducing Automatic SSL/TLS: securing and simplifying origin connectivity

Post Syndicated from Alex Krivit original https://blog.cloudflare.com/introducing-automatic-ssl-tls-securing-and-simplifying-origin-connectivity


During Birthday Week 2022, we pledged to provide our customers with the most secure connection possible from Cloudflare to their origin servers automatically. I’m thrilled to announce we will begin rolling this experience out to customers who have the SSL/TLS Recommender enabled on August 8, 2024. Following this, remaining Free and Pro customers can use this feature beginning September 16, 2024, with Business and Enterprise customers to follow.

Although it took longer than anticipated to roll out, our priority was to achieve an automatic configuration both transparently and without risking any site downtime. Taking this additional time allowed us to balance enhanced security with seamless site functionality, especially since origin server security configuration and capabilities are beyond Cloudflare’s direct control. The new Automatic SSL/TLS setting will maximize and simplify the encryption modes Cloudflare uses to communicate with origin servers by using the SSL/TLS Recommender.

We first talked about this process in 2014: at that time, securing connections was hard to configure, prohibitively expensive, and required specialized knowledge to set up correctly. To help alleviate these pains, Cloudflare introduced Universal SSL, which allowed web properties to obtain a free SSL/TLS certificate to enhance the security of connections between browsers and Cloudflare.

This worked well and was easy because Cloudflare could manage the certificates and connection security from incoming browsers. As a result of that work, the number of encrypted HTTPS connections on the entire Internet doubled at that time. However, the connections made from Cloudflare to origin servers still required manual configuration of the encryption modes to let Cloudflare know the capabilities of the origin.

Today we’re excited to begin the sequel to Universal SSL and make security between Cloudflare and origins automatic and easy for everyone.

History of securing origin-facing connections

Ensuring that more bytes flowing across the Internet are automatically encrypted strengthens the barrier against interception, throttling, and censorship of Internet traffic by third parties.

Generally, two communicating parties (often a client and server) establish a secure connection using the TLS protocol. For a simplified breakdown:

  • The client advertises the list of encryption parameters it supports (along with some metadata) to the server.
  • The server responds back with its own preference of the chosen encryption parameters. It also sends a digital certificate so that the client can authenticate its identity.
  • The client validates the server identity, confirming that the server is who it says it is.
  • Both sides agree on a symmetric secret key for the session that is used to encrypt and decrypt all transmitted content over the connection.

Because Cloudflare acts as an intermediary between the client and our customer’s origin server, two separate TLS connections are established. One between the user’s browser and our network, and the other from our network to the origin server. This allows us to manage and optimize the security and performance of both connections independently.

Unlike securing connections between clients and Cloudflare, the security capabilities of origin servers are not under our direct control. For example, we can manage the certificate (the file used to verify identity and provide context on establishing encrypted connections) between clients and Cloudflare because it’s our job in that connection to provide it to clients, but when talking to origin servers, Cloudflare is the client.

Customers need to acquire and provision an origin certificate on their host. They then have to configure Cloudflare to expect the new certificate from the origin when opening a connection. Needing to manually configure connection security across multiple different places requires effort and is prone to human error.

This issue was discussed in the original Universal SSL blog:

For a site that did not have SSL before, we will default to our Flexible SSL mode, which means traffic from browsers to Cloudflare will be encrypted, but traffic from Cloudflare to a site’s origin server will not. We strongly recommend site owners install a certificate on their web servers so we can encrypt traffic to the origin … Once you’ve installed a certificate on your web server, you can enable the Full or Strict SSL modes which encrypt origin traffic and provide a higher level of security.

Over the years Cloudflare has introduced numerous products to help customers configure how Cloudflare should talk to their origin. These products include a certificate authority to help customers obtain a certificate to verify their origin server’s identity and encryption capabilities, Authenticated Origin Pulls that ensures only HTTPS (encrypted) requests from Cloudflare will receive a response from the origin server, and Cloudflare Tunnels that can be configured to proactively establish secure and private tunnels to the nearest Cloudflare data center. Additionally, the ACME protocol and its corresponding Certbot tooling make it easier than ever to obtain and manage publicly-trusted certificates on customer origins. While these technologies help customers configure how Cloudflare should communicate with their origin server, they still require manual configuration changes on the origin and to Cloudflare settings.

Ensuring certificates are configured appropriately on origin servers and informing Cloudflare about how we should communicate with origins can be anxiety-inducing because misconfiguration can lead to downtime if something isn’t deployed or configured correctly.

To simplify this process and help identify the most secure options that customers could be using without any misconfiguration risk, Cloudflare introduced the SSL/TLS Recommender in 2021. The Recommender works by probing customer origins with different SSL/TLS settings to provide a recommendation whether the SSL/TLS encryption mode for the web property can be improved. The Recommender has been in production for three years and has consistently managed to provide high quality origin-security recommendations for Cloudflare’s customers.

The SSL/TLS Recommender system serves as the brain of the automatic origin connection service that we are announcing today.

How does SSL/TLS Recommendation work?

The Recommender works by actively comparing content on web pages that have been downloaded using different SSL/TLS modes to see if it is safe and risk-free to update the mode Cloudflare uses to connect to origin servers.

Cloudflare currently offers five SSL/TLS modes:

  1. Off: No encryption is used for traffic between browsers and Cloudflare or between Cloudflare and origins. Everything is cleartext HTTP.
  2. Flexible: Traffic from browsers to Cloudflare can be encrypted via HTTPS, but traffic from Cloudflare to the origin server is not. This mode is common for origins that do not support TLS, though upgrading the origin configuration is recommended whenever possible. A guide for upgrading is available here.
  3. Full: Cloudflare matches the browser request protocol when connecting to the origin. If the browser uses HTTP, Cloudflare connects to the origin via HTTP; if HTTPS, Cloudflare uses HTTPS without validating the origin’s certificate. This mode is common for origins that use self-signed or otherwise invalid certificates.
  4. Full (Strict): Similar to Full Mode, but with added validation of the origin server’s certificate, which can be issued by a public CA like Let’s Encrypt or by Cloudflare Origin CA.
  5. Strict (SSL-only origin pull): Regardless of whether the browser-to-Cloudflare connection uses HTTP or HTTPS, Cloudflare always connects to the origin over HTTPS with certificate validation.

HTTP from visitor

HTTPS from visitor

Off

HTTP to origin

HTTP to origin

Flexible

HTTP to origin

HTTP to origin

Full

HTTP to origin

HTTPS without cert validation to origin

Full (strict)

HTTP to origin

HTTPS with cert validation to origin

Strict (SSL-only origin pull)

HTTPS with cert validation to origin

HTTPS with cert validation to origin

The SSL/TLS Recommender works by crawling customer sites and collecting links on the page (like any web crawler). The Recommender downloads content over both HTTP and HTTPS, making GET requests to avoid modifying server resources. It then uses a content similarity algorithm, adapted from the research paper “A Deeper Look at Web Content Availability and Consistency over HTTP/S” (TMA Conference 2020), to determine if content matches. If the content does match, the Recommender makes a determination for whether the SSL/TLS mode can be increased without misconfiguration risk.

The recommendations are currently delivered to customers via email.

When the Recommender is making security recommendations, it errs on the side of maintaining current site functionality to avoid breakage and usability issues. If a website is non-functional, blocks all bots, or has SSL/TLS-specific Page Rules or Configuration Rules, the Recommender may not complete its scans and provide a recommendation. It was designed to maximize domain security, but will not help resolve website or domain functionality issues.

The crawler uses the user agent “Cloudflare-SSLDetector” and is included in Cloudflare’s list of known good bots. It ignores robots.txt (except for rules specifically targeting its user agent) to ensure accurate recommendations.

When downloading content from your origin server over both HTTP and HTTPS and comparing the content, the Recommender understands the current SSL/TLS encryption mode that your website uses and what risk there might be to the site functionality if the recommendation is followed.

Using SSL/TLS Recommender to automatically manage SSL/TLS settings

Previously, signing up for the SSL/TLS Recommender provided a good experience for customers, but only resulted in an email recommendation in the event that a zone’s current SSL/TLS modes could be updated. To Cloudflare, this was a positive signal that customers wanted their websites to have more secure connections to their origin servers – over 2 million domains have enabled the SSL/TLS Recommender. However, we found that a significant number of users would not complete the next step of pushing the button to inform Cloudflare that we could communicate over the upgraded settings. Only 30% of the recommendations that the system provided were followed.

With the system designed to increase security while avoiding any breaking changes, we wanted to provide an option for customers to allow the Recommender to help upgrade their site security, without requiring further manual action from the customer. Therefore, we are introducing a new option for managing SSL/TLS configuration on Cloudflare: Automatic SSL/TLS.

Automatic SSL/TLS uses the SSL/TLS Recommender to make the determination as to what encryption mode is the most secure and safest for a website to be set to. If there is a more secure option for your website (based on your origin certification or capabilities), Automatic SSL/TLS will find it and apply it for your domain. The other option, Custom SSL/TLS, will work exactly like the setting the encryption mode does today. If you know what setting you want, just select it using Custom SSL/TLS, and we’ll use it.

Automatic SSL/TLS is currently meant to service an entire website, which typically works well for those with a single origin. For those concerned that they have more complex setups which use multiple origin servers with different security capabilities, don’t worry. Automatic SSL/TLS will still avoid breaking site functionality by looking for the best setting that works for all origins serving a part of the site’s traffic.

If customers want to segment the SSL/TLS mode used to communicate with the numerous origins that service their domain, they can achieve this by using Configuration Rules. These rules allow you to set more precise modes that Cloudflare should respect (based on path or subdomain or even IP address) to maximize the security of the domain based on your desired Rules criteria. If your site uses SSL/TLS-specific settings in a Configuration Rule or Page rule, those settings will override the zone-wide Automatic and Custom settings.

The goal of Automatic SSL/TLS is to simplify and maximize the origin-facing security for customers on Cloudflare. We want this to be the new default for all websites on Cloudflare, but we understand that not everyone wants this new default, and we will respect your decision for how Cloudflare should communicate with your origin server. If you block the Recommender from completing its crawls, the origin server is non-functional or can’t be crawled, or if you want to opt out of this default and just continue using the same encryption mode you are using today, we will make it easy for you to tell us what you prefer.

How to onboard to Automatic SSL/TLS

To improve the security settings for everyone by default, we are making the following default changes to how Cloudflare configures the SSL/TLS level for all zones:

Starting on August 8, 2024, websites with the SSL/TLS Recommender currently enabled will have the Automatic SSL/TLS setting enabled by default. Enabling does not mean that the Recommender will begin scanning and applying new settings immediately though. There will be a one-month grace period before the first scans begin and the recommended settings are applied. Enterprise (ENT) customers will get a six-week grace period. Origin scans will start getting scheduled by September 9, 2024, for non-Enterprise customers and September 23rd for ENT customers with the SSL Recommender enabled. This will give customers the ability to opt out by removing Automatic SSL/TLS and selecting the Custom mode that they want to use instead.

Further, during the second week of September all new zones signing up for Cloudflare will start seeing the Automatic SSL/TLS setting enabled by default.

Beginning September 16, 2024, remaining Free and Pro customers will start to see the new Automatic SSL/TLS setting. They will also have a one-month grace period to opt out before the scans start taking effect.

Customers in the cohort having the new Automatic SSL/TLS setting applied will receive an email communication regarding the date that they are slated for this migration as well as a banner on the dashboard that mentions this transition as well. If they do not wish for Cloudflare to change anything in their configurations, the process for opt-out of this migration is outlined below.

Following the successful migration of Free and Pro customers, we will proceed to Business and Enterprise customers with a similar cadence. These customers will get email notifications and information in the dashboard when they are in the migration cohort.

The Automatic SSL/TLS setting will not impact users that are already in Strict or Full (strict) mode nor will it impact websites that have opted-out.

Opting out

There are a number of reasons why someone might want to configure a lower-than-optimal security setting for their website. Some may want to set a lower security setting for testing purposes or to debug some behavior. Whatever the reason, the options to opt-out of the Automatic SSL/TLS setting during the migration process are available in the dashboard and API.

To opt-out, simply select Custom SSL/TLS in the dashboard (instead of the enabled Automatic SSL/TLS) and we will continue to use the previously set encryption mode that you were using prior to the migration. Automatic and Custom SSL/TLS modes can be found in the Overview tab of the SSL/TLS section of the dashboard. To enable your preferred mode, select configure.

If you want to opt out via the API you can make this API call on or before the grace period expiration date.

    curl --request PATCH \
        --url https://api.cloudflare.com/client/v4/zones/<insert_zone_tag_here>/settings/ssl_automatic_mode \
        --header 'Authorization: Bearer <insert_api_token_here>' \
        --header 'Content-Type: application/json' \
        --data '{"value":"custom"}'

If an opt-out is triggered, there will not be a change to the currently configured SSL/TLS setting. You are also able to change the security level at any time by going to the SSL/TLS section of the dashboard and choosing the Custom setting you want (similar to how this is accomplished today).

If at a later point you’d like to opt in to Automatic SSL/TLS, that option is available by changing your setting from Custom to Automatic.

What if I want to be more secure now?

We will begin to roll out this change to customers with the SSL/TLS Recommender enabled on August 8, 2024. If you want to enroll in that group, we recommend enabling the Recommender as soon as possible.

If you read this and want to make sure you’re at the highest level of backend security already, we recommend Full (strict) or Strict mode. Directions on how to make sure you’re correctly configured in either of those settings are available here and here.

If you prefer to wait for us to automatically upgrade your connection to the maximum encryption mode your origin supports, please watch your inbox for the date we will begin rolling out this change for you.

Avoiding downtime: modern alternatives to outdated certificate pinning practices

Post Syndicated from Dina Kozlov original https://blog.cloudflare.com/why-certificate-pinning-is-outdated


In today’s world, technology is quickly evolving and some practices that were once considered the gold standard are quickly becoming outdated. At Cloudflare, we stay close to industry changes to ensure that we can provide the best solutions to our customers. One practice that we’re continuing to see in use that no longer serves its original purpose is certificate pinning. In this post, we’ll dive into certificate pinning, the consequences of using it in today’s Public Key Infrastructure (PKI) world, and alternatives to pinning that offer the same level of security without the management overhead.  

PKI exists to help issue and manage TLS certificates, which are vital to keeping the Internet secure – they ensure that users access the correct applications or servers and that data between two parties stays encrypted. The mis-issuance of a certificate can pose great risk. For example, if a malicious party is able to issue a TLS certificate for your bank’s website, then they can potentially impersonate your bank and intercept that traffic to get access to your bank account. To prevent a mis-issued certificate from intercepting traffic, the server can give a certificate to the client and say “only trust connections if you see this certificate and drop any responses that present a different certificate” – this practice is called certificate pinning.

In the early 2000s, it was common for banks and other organizations that handle sensitive data to pin certificates to clients. However, over the last 20 years, TLS certificate issuance has evolved and changed, and new solutions have been developed to help customers achieve the security benefit they receive through certificate pinning, with simpler management, and without the risk of disruption.

Cloudflare’s mission is to help build a better Internet, which is why our teams are always focused on keeping domains secure and online.

Why certificate pinning is causing more outages now than it did before

Certificate pinning is not a new practice, so why are we emphasizing the need to stop using it now? The reason is that the PKI ecosystem is moving towards becoming more agile, flexible, and secure. As a part of this change, certificate authorities (CAs) are starting to rotate certificates and their intermediates, certificates that bridge the root certificate and the domain certificate, more frequently to improve security and encourage automation.

These more frequent certificate rotations are problematic from a pinning perspective because certificate pinning relies on the exact matching of certificates. When a certificate is rotated, the new certificate might not match the pinned certificate on the client side. If the pinned certificate is not updated to reflect the contents of the rotated certificate, the client will reject the new certificate, even if it’s valid and issued by the same CA. This mismatch leads to a failure in establishing a secure connection, causing the domain or application to become inaccessible until the pinned certificate is updated.

Since the start of 2024, we have seen the number of customer reported outages caused by certificate pinning significantly increase. (As of this writing, we are part way through July and Q3 has already seen as many outages as the last three quarters of 2023 combined.)

We can attribute this rise to two major events: Cloudflare migrating away from using DigiCert as a certificate authority and Google and Let’s Encrypt intermediate CA rotations.

Before migrating customer’s certificates away from using DigiCert as the CA, Cloudflare sent multiple notifications to customers to inform them that they should update or remove their certificate pins, so that the migration does not impact their domain’s availability.

However, what we’ve learned is that almost all customers that were impacted by the change were unaware that they had a certificate pin in place. One of the consequences of using certificate pinning is that the “set and forget” mentality doesn’t work, now that certificates are being rotated more frequently. Instead, changes need to be closely monitored to ensure that a regular certificate renewal doesn’t cause an outage. This goes to show that to implement certificate pinning successfully, customers need a robust system in place to track certificate changes and implement them.

We built our Universal SSL pipeline to be resilient and redundant, ensuring that we can always issue and renew a TLS certificate on behalf of our customers, even in the event of a compromise or revocation. CAs are starting to make changes like more frequent certificate rotations to encourage a move towards a more secure ecosystem. Now, it’s up to domain owners to stop implementing legacy practices like certificate pinning, which cause breaking changes, and instead start adopting modern standards that aim to provide the same level of security, but without the management overhead or risk.

Modern standards & practices are making the need for certificate pinning obsolete

Shorter certificate lifetimes

Over the last few years, we have seen certificate lifetimes quickly decrease. Before 2011, a certificate could be valid for up to 96 months (eight years) and now, in 2024, the maximum validity period for a certificate is 1 year. We’re seeing this trend continue to develop, with Google Chrome pushing for shorter CA, intermediate, and certificate lifetimes, advocating for 3 month certificate validity as the new standard.

This push improves security and redundancy of the entire PKI ecosystem in several ways. First, it reduces the scope of a compromise by limiting the amount of time that a malicious party could control a TLS certificate or private key. Second, it reduces reliance on certificate revocation, a process that lacks standardization and enforcement by clients, browsers, and CAs. Lastly, it encourages automation as a replacement for legacy certificate practices that are time-consuming and error-prone.

Cloudflare is moving towards only using CAs that follow the ACME (Automated Certificate Management Environment) protocol, which by default, issues certificates with 90 day validity periods. We have already started to roll this out to Universal SSL certificates and have removed the ability to issue 1-year certificates as a part of our reduced usage of DigiCert.

Regular rotation of intermediate certificates

The CAs that Cloudflare partners with, Let’s Encrypt and Google Trust Services, are starting to rotate their intermediate CAs more frequently. This increased rotation is beneficial from a security perspective because it limits the lifespan of intermediate certificates, reducing the window of opportunity for attackers to exploit a compromised intermediate. Additionally, regular rotations make it easier to revoke an intermediate certificate if it becomes compromised, enhancing the overall security and resiliency of the PKI ecosystem.

Both Let’s Encrypt and Google Trust Services changed their intermediate chains in June 2024. In addition, Let’s Encrypt has started to balance their certificate issuance across 10 intermediates (5 RSA and 5 ECDSA).

Cloudflare customers using Advanced Certificate Manager have the ability to choose their issuing CA. The issue is that even if Cloudflare uses the same CA for a certificate renewal, there is no guarantee that the same certificate chain (root or intermediate) will be used to issue the renewed certificate. As a result, if pinning is used, a successful renewal could cause a full outage for a domain or application.

This happens because certificate pinning relies on the exact matching of certificates. When an intermediate certificate is rotated or changed, the new certificate might not match the pinned certificate on the client side. As a result, the client will reject the renewed certificate, even if it’s a valid certificate issued by the same CA. This mismatch leads to a failure on the client side, causing the domain to become inaccessible until the pinned certificate is updated to reflect the new intermediate certificate. This risk of an unexpected outage is a major downside of continuing to use certificate pinning, especially as CAs increasingly update their intermediates as a security measure.

Increased use of certificate transparency

Certificate transparency (CT) logs provide a standardized framework for monitoring and auditing the issuance of TLS certificates. CT logs help detect misissued or malicious certificates and Cloudflare customers can set up CT monitoring to receive notifications about any certificates issued for their domain. This provides a better mechanism for detecting certificate mis-issuance, reducing the need for pinning.

Why modern standards make certificate pinning obsolete

Together, these practices – shorter certificate lifetimes, regular rotations of intermediate certificates, and increased use of certificate transparency – address the core security concerns that certificate pinning was initially designed to mitigate. Shorter lifetimes and frequent rotations limit the impact of compromised certificates, while certificate transparency allows for real time monitoring and detection of misissued certificates. These advancements are automated, scalable, and robust and eliminate the need for the manual and error-prone process of certificate pinning. By adopting these modern standards, organizations can achieve a higher level of security and resiliency without the management overhead and risk associated with certificate pinning.

Reasons behind continued use of certificate pinning

Originally, certificate pinning was designed to prevent monster-in-the-middle (MITM) attacks by associating a hostname with a specific TLS certificate, ensuring that a client could only access an application if the server presented a certificate issued by the domain owner.

Certificate pinning was traditionally used to secure IoT (Internet of Things) devices, mobile applications, and APIs. IoT devices are usually equipped with more limited processing power and are oftentimes unable to perform software updates. As a result, they’re less likely to perform things like certificate revocation checks to ensure that they’re using a valid certificate. As a result, it’s common for these devices to come pre-installed with a set of trusted certificate pins to ensure that they can maintain a high level of security. However, the increased frequency of certificate changes poses significant risk, as many devices have immutable software, preventing timely updates to certificate pins during renewals.

Similarly, certificate pinning has been employed to secure Android and iOS applications, ensuring that only the correct certificates are served. Despite this, both Apple and Google warn developers against the use of certificate pinning due to the potential for failures if not implemented correctly.

Understanding the trade-offs of different certificate pinning implementations

While certificate pinning can be applied at various levels of the certificate chain, offering different levels of granularity and security, we don’t recommend it due to the challenges and risks associated with its use.

Pinning certificates at the root certificate

Pinning the root certificate instructs a client to only trust certificates issued by that specific Certificate Authority (CA).

Advantages:

  • Simplified management: Since root certificates have long lifetimes (>10 years) and rarely change, pinning at the root reduces the need to frequently update certificate pins, making this the easiest option in terms of management overhead.

Disadvantages:

  • Broader trust: Most Certificate Authorities (CAs) issue their certificates from one root, so pinning a root CA certificate enables the client to trust every certificate issued from that CA. However, this broader trust can be problematic. If the root CA is compromised, every certificate issued by that CA is also compromised, which significantly increases the potential scope and impact of a security breach. This broad trust can therefore create a single point of failure, making the entire ecosystem more vulnerable to attacks.
  • Neglected Maintenance: Root certificates are infrequently rotated, which can lead to a “set and forget” mentality when pinning them. Although it’s rare, CAs do change their roots and when this happens, a correctly renewed certificate will break the pin, causing an outage. Since these pins are rarely updated, resolving such outages can be time-consuming as engineering teams try to identify and locate where the outdated pins have been set.

Pinning certificates at the intermediate certificate

Pinning an intermediate certificate instructs a client to only trust certificates issued by a specific intermediate CA, issued from a trusted root CA. With lifetimes ranging from 3 to 10 years, intermediate certificates offer a better balance between security and flexibility.

Advantages:

  • Better security: Narrows down the trust to certificates issued by a specific intermediate CA.
  • Simpler management: With intermediate CA lifetimes spanning a few years, certificate pins require less frequent updates, reducing the maintenance burden.

Disadvantages:

  • Broad trust: While pinning on an intermediate certificate is more restrictive than pinning on a root certificate, it still allows for a broad range of certificates to be trusted.
  • Maintenance: Intermediate certificates are rotated more frequently than root certificates, requiring more regular updates to pinned certificates.
  • Less predictability: With CAs like Let’s Encrypt issuing their certificates from varying intermediates, it’s no longer possible to predict which certificate chain will be used during a renewal, making it more likely for a certificate renewal to break a certificate pin and cause an outage.

Pinning certificates at the leaf certificate

Pinning the leaf certificate instructs a client to only trust that specific certificate. Although this option offers the highest level of security, it also poses the greatest risk of causing an outage during a certificate renewal.

Advantages:

  • High security: Provides the highest level of security by ensuring that only a specific certificate is trusted, minimizing the risk of a monster-in-the-middle attack.

Disadvantages:

  • Risky: Requires careful management of certificate renewals to prevent outages.
  • Management burden: Leaf certificates have shorter lifetimes, with 90 days becoming the standard, requiring constant updates to the certificate pin to avoid a breaking change during a renewal.

Alternatives to certificate pinning

Given the risks and challenges associated with certificate pinning, we recommend the following as more effective and modern alternatives to achieve the same level of security (preventing a mis-issued certificate from intercepting traffic) that certificate pinning aims to provide.

Shorter certificate lifetimes

Using shorter certificate lifetimes ensures that certificates are regularly renewed and replaced, reducing the risk of misuse of a compromised certificate by limiting the window of opportunity for attackers.

By default, Cloudflare issues 90-day certificates for customers. Customers using Advanced Certificate Manager can request TLS certificates with lifetimes as short as 14 days.

CAA records to restrict which CAs can issue certificates for a domain

Certification Authority Authorization (CAA) DNS records allow domain owners to specify which CAs are allowed to issue certificates for their domain. This adds an extra layer of security by restricting issuance to trusted authorities, providing a similar benefit as pinning a root CA certificate. For example, if you’re using Google Trust Services as your CA, you can add the following CAA DNS record to ensure that only that CA issues certificates for your domain: 

example.com         CAA 0 issue "pki.goog"

By default, Cloudflare sets CAA records on behalf of customers to ensure that certificates can be issued from the CAs that Cloudflare partners with. Customers can choose to further restrict that list of CAs by adding their own CAA records.

Certificate Transparency & monitoring

Certificate Transparency (CT) provides the ability to monitor and audit certificate issuances. By logging certificates in publicly accessible CT logs, organizations are able to monitor, detect, and respond to misissued certificates at the time they are issued.

Cloudflare customers can set up CT Monitoring to receive notifications when certificates are issued in their domain. Today, we notify customers using the product about all certificates issued for their domains. In the future, we will allow customers to filter those notifications, so that they are only notified when an external party that isn’t Cloudflare issues a certificate for the owner’s domain. This product is available to all customers and can be enabled with the click of a button.

Multi-vantage point Domain Control Validation (DCV) checks to prevent mis-issuances

For a CA to issue a certificate, the domain owner needs to prove ownership of the domain by serving Domain Control Validation (DCV) records. While uncommon, one attack vector of DCV validation allows an actor to perform BGP hijacking to spoof the DNS response and trick a CA into mis-issuing a certificate. To prevent this form of attack, CAs have started to perform DCV validation checks from multiple locations to ensure that a certificate is only issued when a full quorum is met.

Cloudflare has developed its own solution that CAs can use to perform multi vantage point DCV checks. In addition, Cloudflare partners with CAs like Let’s Encrypt who continue to develop these checks to support new locations, reducing the risk of a certificate mis-issuance.

Specifying ACME account URI in CAA records

A new enhancement to the ACME protocol allows certificate requesting parties to specify an ACME account URI, the ID of the ACME account that will be requesting the certificates, in CAA records to tighten control over the certificate issuance process. This ensures that only certificates issued through an authorized ACME account are trusted, adding another layer of verification to certificate issuance. Let’s Encrypt supports this extension to CAA records which allows users with a Let’s Encrypt certificate to set a CAA DNS record, such as the following: 

example.com         CAA 0 issue "letsencrypt.org;accounturi=https://acme-v02.api.letsencrypt.org/acme/acct/<account_id>"

With this record, Let’s Encrypt subscribers can ensure that only Let’s Encrypt can issue certificates for their domain and that these certificates were only issued through their ACME account.

Cloudflare will look to support this enhancement automatically for customers in the future.

Conclusion

Years ago, certificate pinning was a valuable tool for enhancing security, but over the last 20 years, it has failed to keep up with new advancements in the certificate ecosystem. As a result, instead of providing the intended security benefit, it has increased the number of outages caused during a successful certificate renewal. With new enhancements in certificate issuance standards and certificate transparency, we’re encouraging our customers and the industry to move towards adopting those new standards and deprecating old ones.

If you’re a Cloudflare customer and are required to pin your certificate, the only way to ensure a zero-downtime renewal is to upload your own custom certificates. We recommend using the staging network to test your certificate renewal to ensure you have updated your certificate pin.

How we ensure Cloudflare customers aren’t affected by Let’s Encrypt’s certificate chain change

Post Syndicated from Dina Kozlov original https://blog.cloudflare.com/shortening-lets-encrypt-change-of-trust-no-impact-to-cloudflare-customers


Let’s Encrypt, a publicly trusted certificate authority (CA) that Cloudflare uses to issue TLS certificates, has been relying on two distinct certificate chains. One is cross-signed with IdenTrust, a globally trusted CA that has been around since 2000, and the other is Let’s Encrypt’s own root CA, ISRG Root X1. Since Let’s Encrypt launched, ISRG Root X1 has been steadily gaining its own device compatibility.

On September 30, 2024, Let’s Encrypt’s certificate chain cross-signed with IdenTrust will expire. After the cross-sign expires, servers will no longer be able to serve certificates signed by the cross-signed chain. Instead, all Let’s Encrypt certificates will use the ISRG Root X1 CA.

Most devices and browser versions released after 2016 will not experience any issues as a result of the change since the ISRG Root X1 will already be installed in those clients’ trust stores. That’s because these modern browsers and operating systems were built to be agile and flexible, with upgradeable trust stores that can be updated to include new certificate authorities.

The change in the certificate chain will impact legacy devices and systems, such as devices running Android version 7.1.1 (released in 2016) or older, as those exclusively rely on the cross-signed chain and lack the ISRG X1 root in their trust store. These clients will encounter TLS errors or warnings when accessing domains secured by a Let’s Encrypt certificate. We took a look at the data ourselves and found that, of all Android requests, 2.96% of them come from devices that will be affected by the change. That’s a substantial portion of traffic that will lose access to the Internet. We’re committed to keeping those users online and will modify our certificate pipeline so that we can continue to serve users on older devices without requiring any manual modifications from our customers.

A better Internet, for everyone

In the past, we invested in efforts like “No Browsers Left Behind” to help ensure that we could continue to support clients as SHA-1 based algorithms were being deprecated. Now, we’re applying the same approach for the upcoming Let’s Encrypt change.

We have made the decision to remove Let’s Encrypt as a certificate authority from all flows where Cloudflare dictates the CA, impacting Universal SSL customers and those using SSL for SaaS with the “default CA” choice.

Starting in June 2024, one certificate lifecycle (90 days) before the cross-sign chain expires, we’ll begin migrating Let’s Encrypt certificates that are up for renewal to use a different CA, one that ensures compatibility with older devices affected by the change. That means that going forward, customers will only receive Let’s Encrypt certificates if they explicitly request Let’s Encrypt as the CA.

The change that Let’s Encrypt is making is a necessary one. For us to move forward in supporting new standards and protocols, we need to make the Public Key Infrastructure (PKI) ecosystem more agile. By retiring the cross-signed chain, Let’s Encrypt is pushing devices, browsers, and clients to support adaptable trust stores.

However, we’ve observed changes like this in the past and while they push the adoption of new standards, they disproportionately impact users in economically disadvantaged regions, where access to new technology is limited.

Our mission is to help build a better Internet and that means supporting users worldwide. We previously published a blog post about the Let’s Encrypt change, asking customers to switch their certificate authority if they expected any impact. However, determining the impact of the change is challenging. Error rates due to trust store incompatibility are primarily logged on clients, reducing the visibility that domain owners have. In addition, while there might be no requests incoming from incompatible devices today, it doesn’t guarantee uninterrupted access for a user tomorrow.

Cloudflare’s certificate pipeline has evolved over the years to be resilient and flexible, allowing us to seamlessly adapt to changes like this without any negative impact to our customers.  

How Cloudflare has built a robust TLS certificate pipeline

Today, Cloudflare manages tens of millions of certificates on behalf of customers. For us, a successful pipeline means:

  1. Customers can always obtain a TLS certificate for their domain
  2. CA related issues have zero impact on our customer’s ability to obtain a certificate
  3. The best security practices and modern standards are utilized
  4. Optimizing for future scale
  5. Supporting a wide range of clients and devices

Every year, we introduce new optimizations into our certificate pipeline to maintain the highest level of service. Here’s how we do it…

Ensuring customers can always obtain a TLS certificate for their domain

Since the launch of Universal SSL in 2014, Cloudflare has been responsible for issuing and serving a TLS certificate for every domain that’s protected by our network. That might seem trivial, but there are a few steps that have to successfully execute in order for a domain to receive a certificate:

  1. Domain owners need to complete Domain Control Validation for every certificate issuance and renewal.
  2. The certificate authority needs to verify the Domain Control Validation tokens to issue the certificate.
  3. CAA records, which dictate which CAs can be used for a domain, need to be checked to ensure only authorized parties can issue the certificate.
  4. The certificate authority must be available to issue the certificate.

Each of these steps requires coordination across a number of parties — domain owners, CDNs, and certificate authorities. At Cloudflare, we like to be in control when it comes to the success of our platform. That’s why we make it our job to ensure each of these steps can be successfully completed.

We ensure that every certificate issuance and renewal requires minimal effort from our customers. To get a certificate, a domain owner has to complete Domain Control Validation (DCV) to prove that it does in fact own the domain. Once the certificate request is initiated, the CA will return DCV tokens which the domain owner will need to place in a DNS record or an HTTP token. If you’re using Cloudflare as your DNS provider, Cloudflare completes DCV on your behalf by automatically placing the TXT token returned from the CA into your DNS records. Alternatively, if you use an external DNS provider, we offer the option to Delegate DCV to Cloudflare for automatic renewals without any customer intervention.

Once DCV tokens are placed, Certificate Authorities (CAs) verify them. CAs conduct this verification from multiple vantage points to prevent spoofing attempts. However, since these checks are done from multiple countries and ASNs (Autonomous Systems), they may trigger a Cloudflare WAF rule which can cause the DCV check to get blocked. We made sure to update our WAF and security engine to recognize that these requests are coming from a CA to ensure they’re never blocked so DCV can be successfully completed.

Some customers have CA preferences, due to internal requirements or compliance regulations. To prevent an unauthorized CA from issuing a certificate for a domain, the domain owner can create a Certification Authority Authorization (CAA) DNS record, specifying which CAs are allowed to issue a certificate for that domain. To ensure that customers can always obtain a certificate, we check the CAA records before requesting a certificate to know which CAs we should use. If the CAA records block all of the CAs that are available in Cloudflare’s pipeline and the customer has not uploaded a certificate from the CA of their choice, then we add CAA records on our customers’ behalf to ensure that they can get a certificate issued. Where we can, we optimize for preference. Otherwise, it’s our job to prevent an outage by ensuring that there’s always a TLS certificate available for the domain, even if it does not come from a preferred CA.

Today, Cloudflare is not a publicly trusted certificate authority, so we rely on the CAs that we use to be highly available. But, 100% uptime is an unrealistic expectation. Instead, our pipeline needs to be prepared in case our CAs become unavailable.

Ensuring that CA-related issues have zero impact on our customer’s ability to obtain a certificate

At Cloudflare, we like to think ahead, which means preventing incidents before they happen. It’s not uncommon for CAs to become unavailable — sometimes this happens because of an outage, but more commonly, CAs have maintenance periods every so often where they become unavailable for some period of time.

It’s our job to ensure CA redundancy, which is why we always have multiple CAs ready to issue a certificate, ensuring high availability at all times. If you’ve noticed different CAs issuing your Universal SSL certificates, that’s intentional. We evenly distribute the load across our CAs to avoid any single point of failure. Plus, we keep a close eye on latency and error rates to detect any issues and automatically switch to a different CA that’s available and performant. You may not know this, but one of our CAs has around 4 scheduled maintenance periods every month. When this happens, our automated systems kick in seamlessly, keeping everything running smoothly. This works so well that our internal teams don’t get paged anymore because everything just works.

Adopting best security practices and modern standards  

Security has always been, and will continue to be, Cloudflare’s top priority, and so maintaining the highest security standards to safeguard our customer’s data and private keys is crucial.

Over the past decade, the CA/Browser Forum has advocated for reducing certificate lifetimes from 5 years to 90 days as the industry norm. This shift helps minimize the risk of a key compromise. When certificates are renewed every 90 days, their private keys remain valid for only that period, reducing the window of time that a bad actor can make use of the compromised material.

We fully embrace this change and have made 90 days the default certificate validity period. This enhances our security posture by ensuring regular key rotations, and has pushed us to develop tools like DCV Delegation that promote automation around frequent certificate renewals, without the added overhead. It’s what enables us to offer certificates with validity periods as low as two weeks, for customers that want to rotate their private keys at a high frequency without any concern that it will lead to certificate renewal failures.

Cloudflare has always been at the forefront of new protocols and standards. It’s no secret that when we support a new protocol, adoption skyrockets. This month, we will be adding ECDSA support for certificates issued from Google Trust Services. With ECDSA, you get the same level of security as RSA but with smaller keys. Smaller keys mean smaller certificates and less data passed around to establish a TLS connection, which results in quicker connections and faster loading times.

Optimizing for future scale

Today, Cloudflare issues almost 1 million certificates per day. With the recent shift towards shorter certificate lifetimes, we continue to improve our pipeline to be more robust. But even if our pipeline can handle the significant load, we still need to rely on our CAs to be able to scale with us. With every CA that we integrate, we instantly become one of their biggest consumers. We hold our CAs to high standards and push them to improve their infrastructure to scale. This doesn’t just benefit Cloudflare’s customers, but it helps the Internet by requiring CAs to handle higher volumes of issuance.

And now, with Let’s Encrypt shortening their chain of trust, we’re going to add an additional improvement to our pipeline — one that will ensure the best device compatibility for all.

Supporting all clients — legacy and modern

The upcoming Let’s Encrypt change will prevent legacy devices from making requests to domains or applications that are protected by a Let’s Encrypt certificate. We don’t want to cut off Internet access from any part of the world, which means that we’re going to continue to provide the best device compatibility to our customers, despite the change.

Because of all the recent enhancements, we are able to reduce our reliance on Let’s Encrypt without impacting the reliability or quality of service of our certificate pipeline. One certificate lifecycle (90 days) before the change, we are going to start shifting certificates to use a different CA, one that’s compatible with the devices that will be impacted. By doing this, we’ll mitigate any impact without any action required from our customers. The only customers that will continue to use Let’s Encrypt are ones that have specifically chosen Let’s Encrypt as the CA.

What to expect of the upcoming Let’s Encrypt change

Let’s Encrypt’s cross-signed chain will expire on September 30th, 2024. Although Let’s Encrypt plans to stop issuing certificates from this chain on June 6th, 2024, Cloudflare will continue to serve the cross-signed chain for all Let’s Encrypt certificates until September 9th, 2024.

90 days or one certificate lifecycle before the change, we are going to start shifting Let’s Encrypt certificates to use a different certificate authority. We’ll make this change for all products where Cloudflare is responsible for the CA selection, meaning this will be automatically done for customers using Universal SSL and SSL for SaaS with the “default CA” choice.

Any customers that have specifically chosen Let’s Encrypt as their CA will receive an email notification with a list of their Let’s Encrypt certificates and information on whether or not we’re seeing requests on those hostnames coming from legacy devices.

After September 9th, 2024, Cloudflare will serve all Let’s Encrypt certificates using the ISRG Root X1 chain. Here is what you should expect based on the certificate product that you’re using:

Universal SSL

With Universal SSL, Cloudflare chooses the CA that is used for the domain’s certificate. This gives us the power to choose the best certificate for our customers. If you are using Universal SSL, there are no changes for you to make to prepare for this change. Cloudflare will automatically shift your certificate to use a more compatible CA.

Advanced Certificates

With Advanced Certificate Manager, customers specifically choose which CA they want to use. If Let’s Encrypt was specifically chosen as the CA for a certificate, we will respect the choice, because customers may have specifically chosen this CA due to internal requirements, or because they have implemented certificate pinning, which we highly discourage.

If we see that a domain using an Advanced certificate issued from Let’s Encrypt will be impacted by the change, then we will send out email notifications to inform those customers which certificates are using Let’s Encrypt as their CA and whether or not those domains are receiving requests from clients that will be impacted by the change. Customers will be responsible for changing the CA to another provider, if they chose to do so.

SSL for SaaS

With SSL for SaaS, customers have two options: using a default CA, meaning Cloudflare will choose the issuing authority, or specifying which CA to use.

If you’re leaving the CA choice up to Cloudflare, then we will automatically use a CA with higher device compatibility.

If you’re specifying a certain CA for your custom hostnames, then we will respect that choice. We will send an email out to SaaS providers and platforms to inform them which custom hostnames are receiving requests from legacy devices. Customers will be responsible for changing the CA to another provider, if they chose to do so.

Custom Certificates

If you directly integrate with Let’s Encrypt and use Custom Certificates to upload your Let’s Encrypt certs to Cloudflare then your certificates will be bundled with the cross-signed chain, as long as you choose the bundle method “compatible” or “modern” and upload those certificates before September 9th, 2024. After September 9th, we will bundle all Let’s Encrypt certificates with the ISRG Root X1 chain. With the “user-defined” bundle method, we always serve the chain that’s uploaded to Cloudflare. If you upload Let’s Encrypt certificates using this method, you will need to ensure that certificates uploaded after September 30th, 2024, the date of the CA expiration, contain the right certificate chain.

In addition, if you control the clients that are connecting to your application, we recommend updating the trust store to include the ISRG Root X1. If you use certificate pinning, remove or update your pin. In general, we discourage all customers from pinning their certificates, as this usually leads to issues during certificate renewals or CA changes.

Conclusion

Internet standards will continue to evolve and improve. As we support and embrace those changes, we also need to recognize that it’s our responsibility to keep users online and to maintain Internet access in the parts of the world where new technology is not readily available. By using Cloudflare, you always have the option to choose the setup that’s best for your application.

For additional information regarding the change, please refer to our developer documentation.

Upcoming Let’s Encrypt certificate chain change and impact for Cloudflare customers

Post Syndicated from Dina Kozlov original https://blog.cloudflare.com/upcoming-lets-encrypt-certificate-chain-change-and-impact-for-cloudflare-customers


Let’s Encrypt, a publicly trusted certificate authority (CA) that Cloudflare uses to issue TLS certificates, has been relying on two distinct certificate chains. One is cross-signed with IdenTrust, a globally trusted CA that has been around since 2000, and the other is Let’s Encrypt’s own root CA, ISRG Root X1. Since Let’s Encrypt launched, ISRG Root X1 has been steadily gaining its own device compatibility.

On September 30, 2024, Let’s Encrypt’s certificate chain cross-signed with IdenTrust will expire. To proactively prepare for this change, on May 15, 2024, Cloudflare will stop issuing certificates from the cross-signed chain and will instead use Let’s Encrypt’s ISRG Root X1 chain for all future Let’s Encrypt certificates.

The change in the certificate chain will impact legacy devices and systems, such as Android devices version 7.1.1 or older, as those exclusively rely on the cross-signed chain and lack the ISRG X1 root in their trust store. These clients may encounter TLS errors or warnings when accessing domains secured by a Let’s Encrypt certificate.

According to Let’s Encrypt, more than 93.9% of Android devices already trust the ISRG Root X1 and this number is expected to increase in 2024, especially as Android releases version 14, which makes the Android trust store easily and automatically upgradable.

We took a look at the data ourselves and found that, from all Android requests, 2.96% of them come from devices that will be affected by the change. In addition, only 1.13% of all requests from Firefox come from affected versions, which means that most (98.87%) of the requests coming from Android versions that are using Firefox will not be impacted.

Preparing for the change

If you’re worried about the change impacting your clients, there are a few things that you can do to reduce the impact of the change. If you control the clients that are connecting to your application, we recommend updating the trust store to include the ISRG Root X1. If you use certificate pinning, remove or update your pin. In general, we discourage all customers from pinning their certificates, as this usually leads to issues during certificate renewals or CA changes.

If you experience issues with the Let’s Encrypt chain change, and you’re using Advanced Certificate Manager or SSL for SaaS on the Enterprise plan, you can choose to switch your certificate to use Google Trust Services as the certificate authority instead.

For more information, please refer to our developer documentation.

While this change will impact a very small portion of clients, we support the shift that Let’s Encrypt is making as it supports a more secure and agile Internet.

Embracing change to move towards a better Internet

Looking back, there were a number of challenges that slowed down the adoption of new technologies and standards that helped make the Internet faster, more secure, and more reliable.

For starters, before Cloudflare launched Universal SSL, free certificates were not attainable. Instead, domain owners had to pay around $100 to get a TLS certificate. For a small business, this is a big cost and without browsers enforcing TLS, this significantly hindered TLS adoption for years. Insecure algorithms have taken decades to deprecate due to lack of support of new algorithms in browsers or devices. We learned this lesson while deprecating SHA-1.

Supporting new security standards and protocols is vital for us to continue improving the Internet. Over the years, big and sometimes risky changes were made in order for us to move forward. The launch of Let’s Encrypt in 2015 was monumental. Let’s Encrypt allowed every domain to get a TLS certificate for free, which paved the way to a more secure Internet, with now around 98% of traffic using HTTPS.

In 2014, Cloudflare launched elliptic curve digital signature algorithm (ECDSA) support for Cloudflare-issued certificates and made the decision to issue ECDSA-only certificates to free customers. This boosted ECDSA adoption by pressing clients and web operators to make changes to support the new algorithm, which provided the same (if not better) security as RSA while also improving performance. In addition to that, modern browsers and operating systems are now being built in a way that allows them to constantly support new standards, so that they can deprecate old ones.

For us to move forward in supporting new standards and protocols, we need to make the Public Key Infrastructure (PKI) ecosystem more agile. By retiring the cross-signed chain, Let’s Encrypt is pushing devices, browsers, and clients to support adaptable trust stores. This allows clients to support new standards without causing a breaking change. It also lays the groundwork for new certificate authorities to emerge.

Today, one of the main reasons why there’s a limited number of CAs available is that it takes years for them to become widely trusted, that is, without cross-signing with another CA. In 2017, Google launched a new publicly trusted CA, Google Trust Services, that issued free TLS certificates. Even though they launched a few years after Let’s Encrypt, they faced the same challenges with device compatibility and adoption, which caused them to cross-sign with GlobalSign’s CA. We hope that, by the time GlobalSign’s CA comes up for expiration, almost all traffic is coming from a modern client and browser, meaning the change impact should be minimal.

AWS Certificate Manager will discontinue WHOIS lookup for email-validated certificates

Post Syndicated from Lerna Ekmekcioglu original https://aws.amazon.com/blogs/security/aws-certificate-manager-will-discontinue-whois-lookup-for-email-validated-certificates/

AWS Certificate Manager (ACM) is a managed service that you can use to provision, manage, and deploy public and private TLS certificates for use with Amazon Web Services (AWS) and your internal connected resources. Today, we’re announcing that ACM will be discontinuing the use of WHOIS lookup for validating domain ownership when you request email-validated TLS certificates.

WHOIS lookup is commonly used to query registration information for a given domain name. This information includes details such as when the domain was originally registered, and contact information for the domain owner and the technical and administrative contacts. Domain owners create and maintain domain registration information outside of ACM in WHOIS, which is a publicly available directory that contains information about domains sponsored by domain registrars and registries. You can use WHOIS lookup to view information about domains that are registered with Amazon Route 53.

Starting June 2024, ACM will no longer send domain validation emails by using WHOIS lookup for new email-validated certificates that you request. Starting October 2024, ACM will no longer send domain validation emails to mailboxes associated with WHOIS lookup for renewal of existing email-validated certificates. ACM will continue to send validation emails to the five common system addresses for the requested domain—we provide a list of these common system addresses in the next section of this post.

In this blog post, we share important details about this change and how you can prepare. Note that if you currently use DNS validation for your certificates requested from ACM, this change doesn’t affect you. These changes only apply to certificates that use email validation.

Background

When you request public certificates through ACM, you need to prove that you own or control the domain before ACM can issue the public certificate. ACM provides two options to validate ownership of a domain: DNS validation and email validation.

AWS recommends that you use DNS validation whenever possible so that ACM can automatically renew certificates that are requested from ACM without requiring action on your part. Email validation is another option that you can use to prove ownership of the domain, but you must manually validate ownership of the domain by using a link provided in an email. Figure 1 is a sample validation email from ACM for the AWS account 111122223333 and AWS US West (Oregon) Region (us-west-2) to validate ownership of the example.com domain.

Figure 1: Sample validation email for example.com domain

Figure 1: Sample validation email for example.com domain

How does ACM know where to send the validation email? Today, as part of the email validation process, ACM sends domain validation emails to the three contact addresses associated with the domain listed in the WHOIS database. These contact addresses are the domain registrant, technical contact, and administrative contact. You create and maintain domain registration information, including these contact addresses, outside of ACM—in the WHOIS database that your domain registrar provides.

Note: If you use Route53, see Updating contact information for a domain to update the contact information for your domain.

ACM also sends validation emails to the following five common system addresses for each domain: 

  • administrator@your_domain_name
  • hostmaster@your_domain_name
  • postmaster@your_domain_name
  • webmaster@your_domain_name
  • admin@your_domain_name

To prove that you own the domain, you must select the validation link included in these emails. ACM also sends validation emails to these same addresses to renew the certificate when the certificate is 45 days from expiry.

What’s changing?

If you currently use email validation for certificates requested from ACM, there are two important dates that you should be aware of:

  1. Starting June 2024, ACM will no longer send domain validation emails by using WHOIS lookup for new email-validated certificates that you request. ACM will continue to send validation emails to the three WHOIS lookup contact addresses for renewal of existing certificates, until October 2024.
  2. Starting October 2024, ACM will no longer send the validation emails to mailboxes associated with WHOIS lookup for existing certificates. After this date, ACM will not send validation emails to the three WHOIS lookup addresses for new or existing certificates.

ACM will continue to send validation emails to the five common system addresses that we listed in the previous section of this post.

Why are we making this change?

We’re making this change to mitigate a potential availability risk for ACM customers. A TLS certificate that ACM issues is valid for up to 395 days, and if you want to keep using it, you need to renew it prior to expiry. To renew an email-validated certificate, you must approve an email that ACM sends. ACM sends the first renewal email 45 days prior to certificate renewal, and if you don’t respond to this email, ACM sends additional reminders prior to expiry. If a certificate bound to one of your AWS resources—such as an Application Load Balancer—expires without being renewed, this could cause an outage for your application.

Some domain registrars that support WHOIS have made changes to the data that they publish to support their compliance with various privacy laws and recommended practices. Over the past several years, we’ve observed that the WHOIS lookup success rate has declined to less than 5 percent. If you rely on the contact addresses listed in the WHOIS database provided by your domain registrar to validate your domain ownership, this might create an availability risk. With a 5 percent success rate for WHOIS lookup, you might not receive validation emails for renewals of your certificates around 95 percent of the time. To provide a consistent mechanism for validating domain ownership when renewing certificates, ACM will only send validation emails to the five common system addresses that we listed in the Background section of this post.

What should you do to prepare?

If you currently monitor one of the five common system addresses (listed previously) for your domains, you don’t need to take any action. Otherwise, we strongly recommend that you create new DNS-validated certificates rather than creating and using email-validated certificates. ACM can automatically renew a DNS-validated certificate, without you taking any action, as long as the CNAME is accurately configured.

Alternatively, if you want to continue using email-validated certificates, we recommend that you monitor at least one of the five common email addresses listed previously. ACM sends the validation emails during certificate issuance for new ACM-issued certificates and during renewal of existing certificates. You can use the ACM describe-certificate API or check the certificate details on the ACM console to see if ACM previously sent validation emails to the relevant system addresses.

In addition, we strongly recommend that you use ACM Certificate Approaching Expiration events to monitor your certificates for expiry and help ensure that you’re notified about certificates that require an action from you to renew. For additional guidance, see How to manage certificate lifecycles using ACM event-driven workflows.

Conclusion

In this blog post, we outlined the changes coming to the email validation process when requesting and renewing certificates from ACM. We also shared the steps that you can take to prepare for this change, including monitoring at least one of the five relevant email addresses for your domains. Remember that these changes only apply to certificates that use email validation, not certificates that use DNS validation. For more information about certificate management on AWS, see the ACM documentation or get started using ACM today in the AWS Management Console.

If you have questions, contact AWS Support or your technical account manager (TAM), or start a new thread on the AWS re:Post ACM Forum. If you have feedback about this post, submit comments in the Comments section below.

 
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Lerna Ekmekcioglu

Lerna Ekmekcioglu

Lerna is a Senior Solutions Architect at AWS where she helps customers build secure, scalable, and highly available workloads. She has over 19 years of platform engineering experience including authentication systems, distributed caching, and multi-Region deployments using IaC and CI/CD to name a few. In her spare time, she enjoys hiking, sightseeing, and backyard astronomy.

Zach Miller

Zach Miller

Zach is a Senior Worldwide Security Specialist Solutions Architect at AWS. His background is in data protection and security architecture, focused on a variety of security domains, including cryptography, secrets management, and data classification. Today, he’s focused on helping enterprise AWS customers adopt and operationalize AWS security services to increase security effectiveness and reduce risk.

Georgy Sebastian

Georgy Sebastian

Georgy is a Senior Software Development Engineer at AWS Cryptography. He has a background in secure system architecture, PKI management, and key distribution. In his free time, he’s an amateur gardener and tinkerer.

Khyati Makim

Khyati Makim

Khyati is a Software Development Manager at AWS Cryptography where she’s focused on building secure solutions with cryptographic best practices. She has 25 years of experience building secure solutions in financial and retail businesses in distributed systems. In her spare time, she enjoys traveling, reading, painting, and spending time with family.

Introducing per hostname TLS settings — security fit to your needs

Post Syndicated from Dina Kozlov original http://blog.cloudflare.com/introducing-per-hostname-tls-settings/

Introducing per hostname TLS settings — security fit to your needs

Introducing per hostname TLS settings — security fit to your needs

One of the goals of Cloudflare is to give our customers the necessary knobs to enable security in a way that fits their needs. In the realm of SSL/TLS, we offer two key controls: setting the minimum TLS version, and restricting the list of supported cipher suites. Previously, these settings applied to the entire domain, resulting in an “all or nothing” effect. While having uniform settings across the entire domain is ideal for some users, it sometimes lacks the necessary granularity for those with diverse requirements across their subdomains.

It is for that reason that we’re excited to announce that as of today, customers will be able to set their TLS settings on a per-hostname basis.

The trade-off with using modern protocols

In an ideal world, every domain could be updated to use the most secure and modern protocols without any setbacks. Unfortunately, that's not the case. New standards and protocols require adoption in order to be effective. TLS 1.3 was standardized by the IETF in April 2018. It removed the vulnerable cryptographic algorithms that TLS 1.2 supported and provided a performance boost by requiring only one roundtrip, as opposed to two. For a user to benefit from TLS 1.3, they need their browser or device to support the new TLS version. For modern browsers and devices, this isn’t a problem – these operating systems are built to dynamically update to support new protocols. But legacy clients and devices were, obviously, not built with the same mindset. Before 2015, new protocols and standards were developed over decades, not months or years, so the clients were shipped out with support for one standard — the one that was used at the time.

If we look at Cloudflare Radar, we can see that about 62.9% of traffic uses TLS 1.3. That’s quite significant for a protocol that was only standardized 5 years ago. But that also means that a significant portion of the Internet continues to use TLS 1.2 or lower.

The same trade-off applies for encryption algorithms. ECDSA was standardized in 2005, about 20 years after RSA. It offers a higher level of security than RSA and uses shorter key lengths, which adds a performance boost for every request. To use ECDSA, a domain owner needs to obtain and serve an ECDSA certificate and the connecting client needs to support cipher suites that use elliptical curve cryptography (ECC). While most publicly trusted certificate authorities now support ECDSA-based certificates, the slow rate of adoption has led many legacy systems to only support RSA, which means that restricting applications to only support ECC-based algorithms could prevent access from those that use older clients and devices.

Balancing the trade-offs

When it comes to security and accessibility, it’s important to find the right middle ground for your business.

To maintain brand, most companies deploy all of their assets under one domain. It’s common for the root domain (e.g. example.com) to be used as a marketing website to provide information about the company, its mission, and the products and services it offers. Then, under the same domain, you might have your company blog (e.g. blog.example.com), your management portal (e.g. dash.example.com), and your API gateway (e.g. api.example.com).

The marketing website and the blog are similar in that they’re static sites that don’t collect information from the accessing users. On the other hand, the management portal and API gateway collect and present sensitive data that needs to be protected.

When you’re thinking about which settings to deploy, you want to consider the data that’s exchanged and the user base. The marketing website and blog should be accessible to all users. You can set them up to support modern protocols for the clients that support them, but you don’t necessarily want to restrict access for users that are accessing these pages from old devices.

The management portal and API gateway should be set up in a manner that provides the best protection for the data exchanged. That means dropping support for less secure standards with known vulnerabilities and requiring new, secure protocols to be used.

To be able to achieve this setup, you need to be able to configure settings for every subdomain within your domain individually.

Per hostname TLS settings – now available!

Customers that use Cloudflare’s Advanced Certificate Manager can configure TLS settings on individual hostnames within a domain. Customers can use this to enable HTTP/2, or to configure the minimum TLS version and the supported ciphers suites on a particular hostname. Any settings that are applied on a specific hostname will supersede the zone level setting. The new capability also allows you to have different settings on a hostname and its wildcard record; which means you can configure example.com to use one setting, and *.example.com to use another.

Let’s say that you want the default min TLS version for your domain to be TLS 1.2, but for your dashboard and API subdomains, you want to set the minimum TLS version to be TLS 1.3. In the Cloudflare dashboard, you can set the zone level minimum TLS version to 1.2 as shown below. Then, to make the minimum TLS version for the dashboard and API subdomains TLS 1.3, make a call to the per-hostname TLS settings API endpoint with the specific hostname and setting.

Introducing per hostname TLS settings — security fit to your needs

This is all available, starting today, through the API endpoint! And if you’d like to learn more about how to use our per-hostname TLS settings, please jump on over to our developer documentation.

Bring your own CA for client certificate validation with API Shield

Post Syndicated from Dina Kozlov original http://blog.cloudflare.com/bring-your-own-ca-for-client-certificate-validation-with-api-shield/

Bring your own CA for client certificate validation with API Shield

Bring your own CA for client certificate validation with API Shield

APIs account for more than half of the total traffic of the Internet. They are the building blocks of many modern web applications. As API usage grows, so does the number of API attacks. And so now, more than ever, it’s important to keep these API endpoints secure. Cloudflare’s API Shield solution offers a comprehensive suite of products to safeguard your API endpoints and now we’re excited to give our customers one more tool to keep their endpoints safe. We’re excited to announce that customers can now bring their own Certificate Authority (CA) to use for mutual TLS client authentication. This gives customers more security, while allowing them to maintain control around their Mutual TLS configuration.

The power of Mutual TLS (mTLS)

Traditionally, when we refer to TLS certificates, we talk about the publicly trusted certificates that are presented by servers to prove their identity to the connecting client. With Mutual TLS, both the client and the server present a certificate to establish a two-way channel of trust. Doing this allows the server to check who the connecting client is and whether or not they’re allowed to make a request. The certificate presented by the client – the client certificate – doesn’t need to come from a publicly trusted CA. In fact, it usually comes from a private or self-signed CA. That’s because the only party that needs to be able to trust it is the connecting server. As long as the connecting server has the client certificate and can check its validity, it doesn’t need to be public.

Securing API endpoints with Mutual TLS

Mutual TLS plays a crucial role in protecting API endpoints. When it comes to safeguarding these endpoints, it's important to have a security model in place that only allows authorized clients to make requests and keeps everyone else out.

That’s why when we launched API Shield in 2020 – a product that’s centered around securing API endpoints – we included mutual TLS client certificate validation as a part of the offering. We knew that mTLS was the best way for our customers to identify and authorize their connecting clients.

When we launched mutual TLS for API Shield, we gave each of our customers a dedicated self-signed CA that they could use to issue client certificates. Once the certificates are installed on devices and mTLS is set up, administrators can enforce that connections can only be made if they present a client certificate issued from that self-signed CA.

This feature has been paramount in securing thousands of endpoints, but it does require our customer to install new client certificates on their devices, which isn’t always possible. Some customers have been using mutual TLS for years with their own CA, which means that the client certificates are already in the wild. Unless the application owner has direct control over the clients, it’s usually arduous, if not impossible, to replace the client certificates with ones issued from Cloudflare’s CA. Other customers may be required to use a CA issued from an approved third party in order to meet regulatory requirements.

To help all of our customers keep their endpoints secure, we’re extending API Shield’s mTLS capability to allow customers to bring their own CA.

Bring your own CA for client certificate validation with API Shield

Get started today

To simplify the management of private PKI at Cloudflare, we created one account level endpoint that enables customers to upload self-signed CAs to use across different Cloudflare products. Today, this endpoint can be used for API shield CAs and for Gateway CAs that are used for traffic inspection.

If you’re an Enterprise customer, you can upload up to five CAs to your account. Once you’ve uploaded the CA, you can use the API Shield hostname association API to associate the CA with the mTLS enabled hostnames. That will tell Cloudflare to start validating the client certificate against the uploaded CA for requests that come in on that hostname. Before you enforce the client certificate validation, you can create a Firewall rule that logs an event when a valid or invalid certificate is served. That will help you determine if you’ve set things up correctly before you enforce the client certificate validation and drop unauthorized requests.

To learn more about how you can use this, refer to our developer documentation.

If you’re interested in using mutual TLS to secure your corporate network, talk to an account representative about using our Access product to do so.

A new, configurable and scalable version of Geo Key Manager, now available in Closed Beta

Post Syndicated from Dina Kozlov original https://blog.cloudflare.com/configurable-and-scalable-geo-key-manager-closed-beta/

A new, configurable and scalable version of Geo Key Manager, now available in Closed Beta

A new, configurable and scalable version of Geo Key Manager, now available in Closed Beta

Today, traffic on the Internet stays encrypted through the use of public and private keys that encrypt the data as it’s being transmitted. Cloudflare helps secure millions of websites by managing the encryption keys that keep this data protected. To provide lightning fast services, Cloudflare stores these keys on our fleet of data centers that spans more than 150 countries. However, some compliance regulations require that private keys are only stored in specific geographic locations.

In 2017, we introduced Geo Key Manager, a product that allows customers to store and manage the encryption keys for their domains in different geographic locations so that compliance regulations are met and that data remains secure. We launched the product a few months before General Data Protection Regulation (GDPR) went into effect and built it to support three regions: the US, the European Union (EU), and a set of our top tier data centers that employ the highest security measures. Since then, GDPR-like laws have quickly expanded and now, more than 15 countries have comparable data protection laws or regulations that include restrictions on data transfer across and/or data localization within a certain boundary.

At Cloudflare, we like to be prepared for the future. We want to give our customers tools that allow them to maintain compliance in this ever-changing environment. That’s why we’re excited to announce a new version of Geo Key Manager — one that allows customers to define boundaries by country, ”only store my private keys in India”, by a region ”only store my private keys in the European Union”, or by a standard, such as “only store my private keys in FIPS compliant data centers” — now available in Closed Beta, sign up here!

Learnings from Geo Key Manager v1

Geo Key Manager has been around for a few years now, and we’ve used this time to gather feedback from our customers. As the demand for a more flexible system grew, we decided to go back to the drawing board and create a new version of Geo Key Manager that would better meet our customers’ needs.

We initially launched Geo Key Manager with support for US, EU, and Highest Security Data centers. Those regions were sufficient at the time, but customers wrestling with data localization obligations in other jurisdictions need more flexibility when it comes to selecting countries and regions. Some customers want to be able to set restrictions to maintain their private keys in one country, some want the keys stored everywhere except in certain countries, and some may want to mix and match rules and say “store them in X and Y, but not in Z”. What we learned from our customers is that they need flexibility, something that will allow them to keep up with the ever-changing rules and policies — and that’s what we set out to build out.

The next issue we faced was scalability.  When we built the initial regions, we included a hard-coded list of data centers that met our criteria for the US, EU, “high security” data center regions.  However, this list was static because the underlying cryptography did not support dynamic changes to our list of data centers. In order to distribute private keys to new data centers that met our criteria, we would have had to completely overhaul the system. In addition to that, our network significantly expands every year, with more than 100 new data centers since the initial launch. That means that any new potential locations that could be used to store private keys are currently not in use, degrading the performance and reliability of customers using this feature.

With our current scale, automation and expansion is a must-have. Our new system needs to dynamically scale every time we onboard or remove a data center from our Network, without any human intervention or large overhaul.

Finally, one of our biggest learnings was that customers make mistakes, such as defining a region that’s so small that availability becomes a concern. Our job is to prevent our customers from making changes that we know will negatively impact them.

Define your own geo-restrictions with the new version of Geo Key Manager

A new, configurable and scalable version of Geo Key Manager, now available in Closed Beta

Cloudflare has significantly grown in the last few years and so has our international customer base. Customers need to keep their traffic regionalized. This region can be as broad as a continent — Asia, for example. Or, it can be a specific country, like Japan.

From our conversations with our customers, we’ve heard that they want to be able to define these regions themselves. This is why today we’re excited to announce that customers will be able to use Geo Key Manager to create what we call “policies”.

A policy can be a single country, defined by two-letter (ISO 3166) country code. It can be a region, such as “EU” for the European Union or Oceania. It can be a mix and match of the two, “country:US or region: EU”.

Our new policy based Geo Key Manager allows you to create allowlist or blocklists of countries and supported regions, giving you control over the boundary in which your private key will be stored. If you’d like to store your private keys globally and omit a few countries, you can do that.

If you would like to store your private keys in the EU and US, you would make the following API call:

curl -X POST "https://api.cloudflare.com/client/v4/zones/zone_id/custom_certificates" \
     -H "X-Auth-Email: [email protected]" \
     -H "X-Auth-Key: auth-key" \
     -H "Content-Type: application/json" \
     --data '{"certificate":"certificate","private_key":"private_key","policy":"(country: US) or (region: EU)", "type": "sni_custom"}'

If you would like to store your private keys in the EU, but not in France, here is how you can define that:

curl -X POST "https://api.cloudflare.com/client/v4/zones/zone_id/custom_certificates" \
     -H "X-Auth-Email: [email protected]" \
     -H "X-Auth-Key: auth-key" \
     -H "Content-Type: application/json" \
     --data '{"certificate":"certificate","private_key":"private_key","policy": "region: EU and (not country: FR)", "type": "sni_custom"}'

Geo Key Manager can now support more than 30 countries and regions. But that’s not all! The superpower of our Geo Key Manager technology is that it doesn’t actually have to be “geo” based, but instead, it’s attribute based. In the future, we’ll have a policy that will allow our customers to define where their private keys are stored based on a compliance standard like FedRAMP or ISO 27001.

Reliability, resiliency, and redundancy

By giving our customers the remote control for Geo Key Manager, we want to make sure that customers understand the impact of their changes on both redundancy and latency.

On the redundancy side, one of our biggest concerns is allowing customers to choose a region small enough that if a data center is removed for maintenance, for example, then availability is drastically impacted. To protect our customers, we’ve added redundancy restrictions. These prevent our customers from setting regions with too few data centers, ensuring that all the data centers within a policy can offer high availability and redundancy.

Not just that, but in the last few years, we’ve significantly improved the underlying networking that powers Geo Key Manager. For more information on how we did that, keep an eye out for a technical deep dive inside Geo Key Manager.

Performance matters

A new, configurable and scalable version of Geo Key Manager, now available in Closed Beta

With the original regions (US, EU, and Highest Security Data Centers), we learned customers may overlook possible latency impacts that occur when defining the key manager to a certain region. Imagine your keys are stored in the US. For your Asia-based customers, there’s going to be some latency impact for the requests that go around the world. Now, with customers being able to define more granular regions, we want to make sure that before customers make that change, they see the impact of it.

If you’re an E-Commerce platform then performance is always top-of-mind. One thing that we’re working on right now is performance metrics for Geo Key Manager policies both from a regional point of view — “what’s the latency impact for Asia based customers?” and from a global point of view — “for anyone in the world, what is the average impact of this policy?”.

By seeing the latency impact, if you see that the impact is unacceptable, you may want to create a separate domain for your service that’s specific to the region that it’s serving.

Closed Beta, now available!

Interested in trying out the latest version of Geo Key Manager? Fill out this form.

Coming soon!

Geo Key Manager is only available via API at the moment. But, we are working on creating an easy-to-use UI for it, so that customers can easily manage their policies and regions. In addition, we’ll surface performance measurements and warnings when we see any degraded impact in terms of performance or redundancy to ensure that customers are mindful when setting policies.

We’re also excited to extend our Geo Key Manager product beyond custom uploaded certificates. In the future, certificates issued through Advanced Certificate Manager or SSL for SaaS will be allowed to add policy based restrictions for the key storage.

Finally, we’re looking to add more default regions to make the selection process simple for our customers. If you have any regions that you’d like us to support, or just general feedback or feature requests related to Geo Key Manager, make a note of it on the form. We love hearing from our customers!

How to evaluate and use ECDSA certificates in AWS Certificate Manager

Post Syndicated from Zachary Miller original https://aws.amazon.com/blogs/security/how-to-evaluate-and-use-ecdsa-certificates-in-aws-certificate-manager/

AWS Certificate Manager (ACM) is a managed service that enables you to provision, manage, and deploy public and private SSL/TLS certificates that you can use to securely encrypt network traffic. You can now use ACM to request Elliptic Curve Digital Signature Algorithm (ECDSA) certificates and associate the certificates with AWS services like Application Load Balancer (ALB) or Amazon CloudFront. As a result, you get the benefit of managed renewal, where ACM can automatically renew ECDSA certificates before they expire. Previously, you could only request certificates with an RSA 2048 key algorithm from ACM. ECDSA certificates could be imported to ACM, but imported certificates cannot use managed renewal.

You can request both ECDSA P-256 and P-384 certificates from ACM. If you do not request an ECDSA certificate, ACM will issue an RSA 2048 certificate by default.

In this blog post, we will briefly examine the differences between RSA and ECDSA certificates, discuss some important considerations when evaluating which certificate type to use, and walk through how you can request an ECDSA certificate and associate it with an application load balancer in AWS.

Cryptographic certificates overview

TLS certificates are used to secure network communications and establish the identity of websites over the internet, as well as the identity of resources on private networks. Public certificates that you request through ACM are obtained from Amazon Trust Services, which is an Amazon managed public certificate authority (CA).

Private certificates are issued through certificate authorities, which you can create and manage by using AWS Private Certificate Authority (AWS Private CA).

Both public and private certificates can help customers identify resources on networks and secure communication between these resources. Public certificates identify resources on the public internet, whereas private certificates do the same for private networks. One key difference is that applications and browsers trust public certificates by default, but an administrator must explicitly configure applications and devices to trust private certificates.

RSA and ECDSA primer

RSA and ECDSA are two widely used public-key cryptographic algorithms—algorithms that use two different keys to encrypt and decrypt data. In the case of TLS, a public key is used to encrypt data, and a private key is used to decrypt data. Public key (or asymmetric key) algorithms are not as computationally efficient as symmetric key algorithms like AES. For this reason, public key algorithms like RSA and ECDSA are primarily used to exchange secrets between two parties initiating a TLS connection. These secrets are then used by both parties to decipher the same symmetric key that actually encrypts the data in transit.

RSA stands for Rivest, Shamir, and Adleman: the researchers who first publicly described this algorithm in 1977. The basic functionality of RSA relies on the idea that large prime numbers are very difficult to efficiently factor. ECDSA, or Elliptic Curve Digital Signature Algorithm, is based on certain unique mathematical properties of elliptic curves that make them very useful for cryptographic operations. The cryptographic utility of ECDSA comes from a concept called the discrete logarithm problem.

Considerations when choosing between RSA and ECDSA

What are the important differences between RSA and ECDSA certificates? When should you choose ECDSA certificates to encrypt network traffic? In this section, we’ll examine the security and performance considerations that help to determine whether ECDSA or RSA certificates are the best choice for your workload.

Security

In cryptography, security is measured as the computational work it takes to exhaust all possible values of a symmetric key in an ideal cipher. An ideal cipher is a theoretical algorithm that has no weaknesses, so you must try every possible key to discover which is the correct key. This is similar to the idea of “brute forcing” a password: trying every possible character combination to find the correct password.

Let’s imagine you have a 112-bit key ideal cipher, which means it would take 2112 tries to exhaust the key space—we would say this cipher has a 112-bit security strength. However, it is important to realize that security strength and key length are not always equal—meaning that an encryption key with a length of 112 bits will not always have a 112-bit security strength.

ECDSA provides higher security strength for lower computational cost. ECDSA P-256, for example, provides 128-bit security strength and is equivalent to an RSA 3072 key. Meanwhile, ECDSA P-384 provides 192-bit security strength, equivalent to the key associated with an RSA 7680 certificate. In other words, an ECDSA P-384 key would require 2192 tries to exhaust the key space.

The following table provides an in-depth comparison of the different security strengths for RSA key lengths and ECDSA curve types. Note that only RSA 2048 and ECDSA P-256 and P-384 are currently issued by ACM. However, ACM does support the import and usage of the other certificate types listed in the table. For more information, see Importing certificates into AWS Certificate Manager.

Security strength RSA key length ECDSA curve type
80-bit 1024 160
112-bit 2048 224
128-bit 3072 256
192-bit 7680 384
256-bit 15360 512

Performance

ECDSA provides a higher security strength (for a given key length) than RSA but does not add performance overhead. For example, ECDSA P-256 is as performant as RSA 2048 while providing security strength that is comparable to RSA 3072.

ECDSA certificates also have up to a 50% smaller certificate size when compared to RSA certificates, and are therefore more suitable to protect data-in-transit over low bandwidth or for applications with limited memory and storage, such as Internet of Things (IoT) devices.

Take a look at the following certificate examples; you can see the size difference between RSA and ECDSA certificates.

RSA 2048: ECDSA P-256 (EC_prime256v1):
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----		 -----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

Consider a small IoT sensor device that tracks temperature in an office building. This device typically has very low storage capacity and compute power, so the smaller ECDSA certificate will be easier to process and store. In the case of an IoT device, you might not be able to store the entire RSA certificate chain on the device due to memory limitations and the larger size of RSA certificates. This can make it more difficult to validate the chain of trust for that certificate.

Using ECDSA, customers can take advantage of the smaller size of the certificates (and the certificate trust chain) and store the entire chain of trust on the IoT device itself, enabling the IoT device to more easily validate the certificate.

When should I use ECDSA certificates from ACM?

In general, you should consider using ECDSA certificates wherever possible, because they provide stronger security (for a given key length) compared to RSA, without impacting performance. You can also choose to issue ECDSA certificates from ACM to implement 128-bit or 192-bit TLS security, where previously you could request up to 112-bit security from ACM by using RSA 2048 certificates.

ECDSA certificates are strongly recommended for applications that need to securely send data over low-bandwidth connections, or when you are using IoT devices that might not have much memory or computational power to store and process the larger certificate sizes that RSA offers.

If your application is not ECDSA compatible, you will need to continue using RSA certificates. RSA 2048 remains the default certificate type issued by ACM, in order to prevent compatibility issues with legacy applications or with applications that do not support ECDSA certificate types. We will provide links to check if your application is compatible with ECDSA certificate types in the next section of this blog.

Getting started with ECDSA certificates

Modern browsers and operating systems are ECDSA compatible. That said, some custom applications might not be ECDSA compatible. You can check whether your calling application is ECDSA compatible by accessing the following links from your application:

ECDSA P-256

ECDSA P-384

When you access one of these links, you should see a message stating “Expected Status: good”. This indicates that the application is ECDSA compatible. See Figure 1 for an example of a successful result.

Figure 1: ECDSA application compatibility example

Figure 1: ECDSA application compatibility example

When you terminate your TLS traffic with ALB, you can work around compatibility concerns by binding both ECDSA and RSA certificates for a given domain. ALB will prioritize and present the ECDSA certificate when the calling application is ECDSA compatible and will use the RSA certificate if the calling application is not ECDSA compatible. We’ll walk through this configuration in the demonstration portion of this post.

How to request an ECDSA certificate from ACM

You can use the ACM console, APIs, or AWS Command Line Interface (AWS CLI) to issue public or private ECDSA P-256 and P-384 TLS certificates. When you request certificates by using the API or AWS CLI, you can use the request-certificate API action with either EC_prime256v1 or EC_secp384r1 as the key-algorithm parameter to request a P-256 or P-384 ECDSA certificate, respectively.

Certificates have a defined validity period, and ACM will attempt to renew certificates that were issued by ACM and that are in use before they expire. ACM will also attempt to automatically bind the renewed certificates with an integrated service. ACM issued private ECDSA certificates can also be exported and used on other workloads to terminate TLS traffic.

Associate an ECDSA certificate with an Application Load Balancer for TLS

To demonstrate how to request and use ECDSA certificates from ACM, let’s examine a common use case: requesting a public certificate from ACM and associating it with an ALB. This walkthrough will also include requesting an RSA 2048 certificate and associating it with the same ALB, to facilitate TLS connections for applications that do not support ECDSA. ALB will prioritize and present the ECDSA certificate when the calling application is ECDSA compatible, and will use the RSA certificate if the calling application is not ECDSA compatible.

This procedure has the following prerequisites:

  • An AWS Identity and Access Management (IAM) user or role that has the appropriate permissions to request certificates from ACM and create an ALB
  • A public domain that you own
  • A public subnet, or IAM permissions to create one

To request an ECDSA certificate from ACM

  1. Navigate to the ACM console and choose Request a certificate.
  2. Choose Request a public certificate, and then choose Next.
  3. For Fully qualified domain name, enter your domain name.
  4. Choose DNS validation. DNS validation is recommended wherever possible, because it enables automatic renewal of ACM issued certificates with no action required by the domain owner. If you use Amazon Route 53, you can use ACM to directly update your DNS records. DNS-validated certificates will be renewed by ACM as long as the certificate is in use and the DNS record is in place.
    Figure 2: Requesting a public ECDSA certificate

    Figure 2: Requesting a public ECDSA certificate

  5. In the Key algorithm options section, select your preferred algorithm based on your security requirements:
    • ECDSA P-256 — Equivalent in security strength to RSA 3072
    • ECDSA P-384 — Equivalent in security strength to RSA 7680
    Figure 3: Key algorithms

    Figure 3: Key algorithms

  6. (Optional) Add tags to help you identify and manage your certificate. You can find more information on using tags in Tagging AWS resources in the AWS General Reference.
  7. Choose Request to request the public certificate.

    The certificate will now be in the Pending Validation state until the domain can be validated, either through DNS or email validation, depending on your selection in the previous steps. For information on how to validate ownership of the domain name or names, see Validating domain ownership in the AWS Certificate Manager User Guide.

  8. Take note of the certificate ARN; you will need this later to identify the certificate.

To request an RSA 2048 certificate from ACM

  1. To request a public RSA 2048 certificate, use the same steps noted in the preceding section, but select RSA 2048 in the Key algorithm options section.
  2. Make sure that both certificates you request have the same fully qualified domain name.

    For more information on requesting public certificates from ACM, see Requesting a public certificate.

To create a new Application Load Balancer and associate a default certificate

  1. Navigate to the Amazon Elastic Compute Cloud (EC2) console. In the left navigation pane, under Load Balancing, choose Load Balancers.
  2. Choose Create Load Balancer.

    For this post, we will use an Application Load Balancer. You can view more details on each type of Load Balancer, and see a feature-to-feature breakdown, on the Elastic Load Balancing features page.

  3. For the Application Load Balancer type, choose Create.
  4. Enter a name for your load balancer.
  5. Select the scheme and IP address type of the application load balancer. For this post, we will choose Internet-facing for the scheme and use the IPv4 address type.
    Figure 4: Create an application load balancer

    Figure 4: Create an application load balancer

  6. In the Network mapping section of this page, you will need to select a VPC and at least two Availability Zones and one public subnet per zone. If you do not already have a public subnet in two Availability Zones, see these instructions for creating a public subnet.
    Figure 5: Network mapping for ALB

    Figure 5: Network mapping for ALB

  7. Next, you need to create a secure listener. Under Listeners and routing, choose the HTTPS protocol (Port 443) in the drop-down list.
  8. Under Default action, choose Forward. For Target Group, select a target group for the ALB to send traffic to.
  9. Under Secure listener settings, you will associate the RSA 2048 certificate with the new Application Load Balancer.

    Choose the appropriate security policy for your organization—you can compare policies on this page.

  10. Under Default SSL/TLS certificate, verify that From ACM is selected, and then in the drop-down list, select the RSA certificate you requested earlier.

    Note: We are using the RSA certificate as the default so that the ALB will use this certificate if the connecting client does not support ECDSA or the Server Name Indication (SNI) protocol. This is to maximize availability and compatibility with legacy applications.

    Figure 6: Secure listener settings

    Figure 6: Secure listener settings

  11. (Optional) Add tags to the Application Load Balancer.
  12. Review your selections, and then choose Create load balancer.
    Figure 7: Review and create load balancer

    Figure 7: Review and create load balancer

To associate the ECDSA certificate with the Application Load Balancer

  1. In the EC2 console, select the new ALB you just created, and choose the Listeners tab.
  2. In the SSL Certificate column, you should see the default certificate you added when you created the ALB. Choose View/edit certificates to see the full list of certificates associated with this ALB.
    Figure 8: ALB listeners

    Figure 8: ALB listeners

  3. Under Listener certificates for SNI, choose Add certificate.
    Figure 9: Listener certificates for SNI

    Figure 9: Listener certificates for SNI

  4. Under ACM and IAM certificates, select the ECDSA certificate you requested earlier.

    Note: You can use the certificate ARN to identify the appropriate certificate.

  5. Choose Include as pending below to add the ECDSA certificate to the listener.
    Figure 10: Adding the ECDSA certificate to the load balancer listener

    Figure 10: Adding the ECDSA certificate to the load balancer listener

  6. Under Listener certificates for SNI, confirm that the ECDSA certificate is listed as pending, and choose Add pending certificates.
    Figure 11: Confirm addition of pending certificates

    Figure 11: Confirm addition of pending certificates

Great! We’ve used ACM to request a public ECDSA certificate and a public RSA 2048 certificate. Next, we associated both of these certificates with an Application Load Balancer to facilitate TLS communications between the load balancer and client devices.

If clients support the SNI protocol, the ALB uses a smart certificate selection algorithm. The load balancer will select the best certificate that the client can support from the certificate list. Certificate selection is based on the following criteria, in the following order:

  • Public key algorithm (prefer ECDSA over RSA)
  • Hashing algorithm (prefer SHA over MD5)
  • Key length (prefer the longest key)
  • Validity period

In the earlier example, this means if clients support SNI and ECDSA, the ECDSA certificate will be prioritized and presented to the client. If the client does not support SNI or ECDSA, the RSA certificate will be used to maximize compatibility with legacy applications.

Conclusion

In this blog post, we discussed the basic differences between RSA and ECDSA certificates, when you might choose ECDSA over RSA, and how you can use AWS Certificate Manager to request public or private ECDSA certificates. We also covered how to request a public ECDSA certificate from ACM and associate it with an Application Load Balancer. Finally, we showed you how to request an RSA 2048 certificate and associate it with the same load balancer to facilitate TLS for applications that do not support ECDSA certificates.

To learn more about using ACM to issue ECDSA certificates, see our YouTube video: AWS Certificate Manager (ACM) – How to evaluate and use ECDSA certificates. You can also refer to the AWS Certificate Manager documentation for more details, and then get started issuing ECDSA certificates with AWS Certificate Manager.

 
If you have feedback about this post, submit comments in the Comments section below. If you have questions about this post, contact AWS Support.

Want more AWS Security news? Follow us on Twitter.

Zach Miller

Zach Miller

Zach is a Senior Security Specialist Solutions Architect at AWS. His background is in data protection and security architecture, focused on a variety of security domains, including cryptography, secrets management, and data classification. Today, he is focused on helping enterprise AWS customers adopt and operationalize AWS security services to increase security effectiveness and reduce risk.

Chandan Kundapur

Chandan Kundapur

Chandan is a Senior Technical Product Manager on the AWS Certificate Manager (ACM) team. With over 15 years of cybersecurity experience, he has a passion for driving PKI product strategy.

Critical Vulnerability in Open SSL

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/10/critical-vulnerability-in-open-ssl.html

There are no details yet, but it’s really important that you patch Open SSL 3.x when the new version comes out on Tuesday.

How bad is “Critical”? According to OpenSSL, an issue of critical severity affects common configurations and is also likely exploitable.

It’s likely to be abused to disclose server memory contents, and potentially reveal user details, and could be easily exploited remotely to compromise server private keys or execute code execute remotely. In other words, pretty much everything you don’t want happening on your production systems.

Slashdot thread.

Total TLS: one-click TLS for every hostname you have

Post Syndicated from Dina Kozlov original https://blog.cloudflare.com/total-tls-one-click-tls-for-every-hostname/

Total TLS: one-click TLS for every hostname you have

Total TLS: one-click TLS for every hostname you have

Today, we’re excited to announce Total TLS — a one-click feature that will issue individual TLS certificates for every subdomain in our customer’s domains.

By default, all Cloudflare customers get a free, TLS certificate that covers the apex and wildcard (example.com, *.example.com) of their domain. Now, with Total TLS, customers can get additional coverage for all of their subdomains with just one-click! Once enabled, customers will no longer have to worry about insecure connection errors to subdomains not covered by their default TLS certificate because Total TLS will keep all the traffic bound to the subdomains encrypted.

A primer on Cloudflare’s TLS certificate offerings

Universal SSL — the “easy” option

In 2014, we announced Universal SSL — a free TLS certificate for every Cloudflare customer. Universal SSL was built to be a simple “one-size-fits-all” solution. For customers that use Cloudflare as their authoritative DNS provider, this certificate covers the apex and a wildcard e.g. example.com and *.example.com. While a Universal SSL certificate provides sufficient coverage for most, some customers have deeper subdomains like a.b.example.com for which they’d like TLS coverage. For those customers, we built Advanced Certificate Manager — a customizable platform for certificate issuance that allows customers to issue certificates with the hostnames of their choice.

Advanced certificates — the “customizable” option

For customers that want flexibility and choice, we build Advanced certificates which are available as a part of Advanced Certificate Manager. With Advanced certificates, customers can specify the exact hostnames that will be included on the certificate.

That means that if my Universal SSL certificate is insufficient, I can use the Advanced certificates UI or API to request a certificate that covers “a.b.example.com” and “a.b.c.example.com”. Today, we allow customers to place up to 50 hostnames on an Advanced certificate. The only caveat — customers have to tell us which hostnames to protect.

This may seem trivial, but some of our customers have thousands of subdomains that they want to keep protected. We have customers with subdomains that range from a.b.example.com to a.b.c.d.e.f.example.com and for those to be covered, customers have to use the Advanced certificates API to tell us the hostname that they’d like us to protect. A process like this is error-prone, not easy to scale, and has been rejected as a solution by some of our largest customers.

Instead, customers want Cloudflare to issue the certificates for them. If Cloudflare is the DNS provider then Cloudflare should know what subdomains need protection. Ideally, Cloudflare would issue a TLS certificate for every subdomain that’s proxying its traffic through the Cloudflare Network… and that’s where Total TLS comes in.

Enter Total TLS: easy, customizable, and scalable

Total TLS is a one-click button that signals Cloudflare to automatically issue TLS certificates for every proxied DNS record in your domain. Once enabled, Cloudflare will issue individual certificates for every proxied hostname. This way, you can add as many DNS records and subdomains as you need to, without worrying about whether they’ll be covered by a TLS certificate.

If you have a DNS record for a.b.example.com, we’ll issue a TLS certificate with the hostname a.b.example.com. If you have a wildcard record for *.a.b.example.com then we’ll issue a TLS certificate for “*.a.b.example.com”. Here’s an example of what this will look like in the Edge Certificates table of the dashboard:

Total TLS: one-click TLS for every hostname you have

Available now

Total TLS is now available to use as a part of Advanced Certificate Manager for domains that use Cloudflare as an Authoritative DNS provider. One of the superpowers of having Cloudflare as your DNS provider is that we’ll always add the proper Domain Control Validation (DCV) records on your behalf to ensure successful certificate issuance and renewal.

Enabling Total TLS is easy — you can do it through the Cloudflare dashboard or via API. In the SSL/TLS tab of the Cloudflare dashboard, navigate to Total TLS. There, choose the issuing CA — Let’s Encrypt, Google Trust Services, or No Preference, if you’d like Cloudflare to select the CA on your behalf then click on the toggle to enable the feature.

Total TLS: one-click TLS for every hostname you have

But that’s not all…

One pain point that we wanted to address for all customers was visibility. From looking at support tickets and talking to customers, one of the things that we realized was that customers don’t always know whether their domain is covered by a TLS certificate —  a simple oversight that can result in downtime or errors.

To prevent this from happening, we are now going to warn every customer if we see that the proxied DNS record that they’re creating, viewing, or editing doesn’t have a TLS certificate covering it. This way, our customers can get a TLS certificate issued before the hostname becomes publicly available, preventing visitors from encountering this error:

Total TLS: one-click TLS for every hostname you have

Join the mission

At Cloudflare, we love building products that help secure all Internet properties. Interested in achieving this mission with us? Join the team!

Amazon introduces dynamic intermediate certificate authorities

Post Syndicated from Adina Lozada original https://aws.amazon.com/blogs/security/amazon-introduces-dynamic-intermediate-certificate-authorities/

AWS Certificate Manager (ACM) is a managed service that lets you provision, manage, and deploy public and private Secure Sockets Layer/Transport Layer Security (SSL/TLS) certificates for use with Amazon Web Services (AWS) and your internal connected resources. Starting October 11, 2022, at 9:00 AM Pacific Time, public certificates obtained through ACM will be issued from one of the multiple intermediate certificate authorities (CAs) that Amazon manages. In this blog post, we share important details about this change and how you can prepare.

What is changing and why?

Public certificates that you request through ACM are obtained from Amazon Trust Services, which is a public certificate authority (CA) that Amazon manages. Like other public CAs, Amazon Trust Services CAs have a structured trust hierarchy. The public certificate issued to you, also known as the leaf certificate, can chain to one or more intermediate CAs and then to the Amazon Trust Services root CA. The Amazon Trust Services root CA is trusted by default by most and operating systems. This is why Amazon can issue public certificates that are trusted by these systems.

Starting October 11, 2022 at 9:00 AM Pacific Time, public certificates obtained through ACM will be issued from one of the multiple intermediate CAs that Amazon manages. These intermediate CAs chain to an existing Amazon Trust Services root CA. With this change, leaf certificates issued to you will be signed by different intermediate CAs. Before this change, Amazon maintained a limited number of intermediate CAs and issued and renewed certificates from the same intermediate CAs.

Amazon is making this change to create a more resilient and agile certificate infrastructure that will help us respond more quickly to future requirements. This change also presents an opportunity to correct a known issue related to delayed revocation of a subordinate CA and help minimize the scope of impact for new risks that might emerge in the future.

What can I do to prepare?

Most customers won’t experience an impact from this change. Browsers and most applications will continue to work just as they do now, because these services trust the Amazon Trust Services root CA and not a specific intermediate CA. If you’re using one of the standard operating systems and web browsers that are listed in the next section of this post, you don’t need to take any action.

If you use intermediate CA information through certificate pinning, you will need to make changes and pin to an Amazon Trust Services root CA instead of an intermediate CA or leaf certificate. Certificate pinning is a process in which your application that initiates the TLS connection only trusts a specific public certificate through one or more certificate variables that you define. If the pinned certificate is replaced, your application won’t initiate the connection. AWS recommends that you don’t use certificate pinning because it introduces an availability risk. However, if your use case requires certificate pinning, AWS recommends that you pin to an Amazon Trust Services root CA instead of an intermediate CA or leaf certificate. When you pin to an Amazon Trust Services root CA, you should pin to all of the root CAs shown in the following table.

Amazon Trust Services root CA certificates

Distinguished name SHA-256 hash of subject public key information Test URL
CN=Amazon Root CA
1,O=Amazon,C=US		 fbe3018031f9586bcbf41727e417b7d1c45c2f47f93be372a17b96b50757d5a2 Test URL
CN=Amazon Root CA
2,O=Amazon,C=US		 7f4296fc5b6a4e3b35d3c369623e364ab1af381d8fa7121533c9d6c633ea2461 Test URL
CN=Amazon Root CA
3,O=Amazon,C=US		 36abc32656acfc645c61b71613c4bf21c787f5cabbee48348d58597803d7abc9 Test URL
CN=Amazon Root CA
4,O=Amazon,C=US		 f7ecded5c66047d28ed6466b543c40e0743abe81d109254dcf845d4c2c7853c5 Test URL

To test that your trust store contains the Amazon Trust Services root CA, see the preceding table, which lists the Amazon Trust Services root CA certificates, and choose each test URL in the table. If the test URL works, you should see a message that says Expected Status: Good, along with the certificate chain. If the test URL doesn’t work, you will receive an error message that indicates the connection has failed.

What should I do if the Amazon Trust Services CAs are not in my trust store?

If your application is using a custom trust store, you must add the Amazon Trust Services root CAs to your application’s trust store. The instructions for doing this vary based on the application or service. Refer to the documentation for the application or service that you’re using.

If your tests of any of the test URLs failed, you must update your trust store. The simplest way to update your trust store is to upgrade the operating system or browser that you’re using.

The following operating systems use the Amazon Trust Services CAs:

  • Amazon Linux (all versions)
  • Microsoft Windows versions, with updates installed, from January 2005, Windows Vista, Windows 7, Windows Server 2008, and newer versions
  • Mac OS X 10.4 with Java for Mac OS X 10.4 Release 5, Mac OS X 10.5, and newer versions
  • Red Hat Enterprise Linux 5 (March 2007 release), Linux 6, and Linux 7 and CentOS 5, CentOS 6, and CentOS 7
  • Ubuntu 8.10
  • Debian 5.0
  • Java 1.4.2_12, Java 5 update 2, and all newer versions, including Java 6, Java 7, and Java 8

Modern browsers trust Amazon Trust Services CAs. To update the certificate bundle in your browser, update your browser. For instructions on how to update your browser, see the update page for your browser:

Where can I get help?

If you have questions, contact AWS Support or your technical account manager (TAM), or start a new thread on the AWS re:Post ACM Forum. If you have feedback about this post, submit comments in the Comments section below.

Want more AWS Security news? Follow us on Twitter.

Adina Lozada

Adina Lozada

Adina is a Principal Technical Program Manager on the Amazon Certificate Manager (ACM) team with over 18 years of professional experience as a multi-disciplined, security careerist in both public and private sector. She works with AWS services to help make complex, cross-functional program delivery faster for our customers.

Chandan Kundapur

Chandan Kundapur

Chandan is a, Sr. Technical Product Manager on the Amazon Certificate Manager (ACM) team. With over 15 years of cyber security experience, he has a passion for driving our product strategy to help AWS customers identify and secure their resources and endpoints with public and private certificates.

Introducing new Cloudflare for SaaS documentation

Post Syndicated from Mia Malden original https://blog.cloudflare.com/introducing-new-cloudflare-for-saas-documentation/

Introducing new Cloudflare for SaaS documentation

Introducing new Cloudflare for SaaS documentation

As a SaaS provider, you’re juggling many challenges while building your application, whether it’s custom domain support, protection from attacks, or maintaining an origin server. In 2021, we were proud to announce Cloudflare for SaaS for Everyone, which allows anyone to use Cloudflare to cover those challenges, so they can focus on other aspects of their business. This product has a variety of potential implementations; now, we are excited to announce a new section in our Developer Docs specifically devoted to Cloudflare for SaaS documentation to allow you take full advantage of its product suite.

Cloudflare for SaaS solution

You may remember, from our October 2021 blog post, all the ways that Cloudflare provides solutions for SaaS providers:

  • Set up an origin server
  • Encrypt your customers’ traffic
  • Keep your customers online
  • Boost the performance of global customers
  • Support custom domains
  • Protect against attacks and bots
  • Scale for growth
  • Provide insights and analytics
Introducing new Cloudflare for SaaS documentation

However, we received feedback from customers indicating confusion around actually using the capabilities of Cloudflare for SaaS because there are so many features! With the existing documentation, it wasn’t 100% clear how to enhance security and performance, or how to support custom domains. Now, we want to show customers how to use Cloudflare for SaaS to its full potential by including more product integrations in the docs, as opposed to only focusing on the SSL/TLS piece.

Bridging the gap

Cloudflare for SaaS can be overwhelming with so many possible add-ons and configurations. That’s why the new docs are organized into six main categories, housing a number of new, detailed guides (for example, WAF for SaaS and Regional Services for SaaS):

Introducing new Cloudflare for SaaS documentation

Once you get your SaaS application up and running with the Get Started page, you can find which configurations are best suited to your needs based on your priorities as a provider. Even if you aren’t sure what your goals are, this setup outlines the possibilities much more clearly through a number of new documents and product guides such as:

Instead of pondering over vague subsection titles, you can peruse with purpose in mind. The advantages and possibilities of Cloudflare for SaaS are highlighted instead of hidden.

Possible configurations

This setup facilitates configurations much more easily to meet your goals as a SaaS provider.

For example, consider performance. Previously, there was no documentation surrounding reduced latency for SaaS providers. Now, the Performance section explains the automatic benefits to your performance by onboarding with Cloudflare for SaaS. Additionally, it offers three options of how to reduce latency even further through brand-new docs:

Similarly, the new organization offers WAF for SaaS as a previously hidden security solution, extending providers the ability to enable automatic protection from vulnerabilities and the flexibility to create custom rules. This is conveniently accompanied by a step-by-step tutorial using Cloudflare Managed Rulesets.

What’s next

While this transition represents an improvement in the Cloudflare for SaaS docs, we’re going to expand its accessibility even more. Some tutorials, such as our Managed Ruleset Tutorial, are already live within the tile. However, more step-by-step guides for Cloudflare for SaaS products and add-ons will further enable our customers to take full advantage of the available product suite. In particular, keep an eye out for expanding documentation around using Workers for Platforms.

Check it out

Visit the new Cloudflare for SaaS tile to see the updates. If you are a SaaS provider interested in extending Cloudflare benefits to your customers through Cloudflare for SaaS, visit our Cloudflare for SaaS overview and our Plans page.

Introducing: Backup Certificates

Post Syndicated from Dina Kozlov original https://blog.cloudflare.com/introducing-backup-certificates/

Introducing: Backup Certificates

At Cloudflare, we pride ourselves in giving every customer the ability to provision a TLS certificate for their Internet application — for free. Today, we are responsible for managing the certificate lifecycle for almost 45 million certificates from issuance to deployment to renewal. As we build out the most resilient, robust platform, we want it to be “future-proof” and resilient against events we can’t predict.

Events that cause us to re-issue certificates for our customers, like key compromises, vulnerabilities, and mass revocations require immediate action. Otherwise, customers can be left insecure or offline. When one of these events happens, we want to be ready to mitigate impact immediately. But how?

By having a backup certificate ready to deploy — wrapped with a different private key and issued from a different Certificate Authority than the primary certificate that we serve.

Introducing: Backup Certificates

Events that lead to certificate re-issuance

Cloudflare re-issues certificates every day — we call this a certificate renewal. Because certificates come with an expiration date, when Cloudflare sees that a certificate is expiring soon, we initiate a new certificate renewal order. This way, by the time the certificate expires, we already have an updated certificate deployed and ready to use for TLS termination.

Unfortunately, not all certificate renewals are initiated by the expiration date. Sometimes, unforeseeable events like key compromises can lead to certificate renewals. This is because a new key needs to be issued, and therefore a corresponding certificate does as well.

Key Compromises

A key compromise is when an unauthorized person or system obtains the private key that is used to encrypt and decrypt secret information — security personnel’s worst nightmare. Key compromises can be the result of a vulnerability, such as Heartbleed, where a bug in a system can cause the private key to be leaked. They can also be the result of malicious actions, such as a rogue employee accessing unauthorized information. In the event of a key compromise, it’s crucial that (1) new private keys are immediately issued, (2) new certificates are deployed, and (3) the old certificates are revoked.

The Heartbleed Vulnerability

In 2014, the Heartbleed vulnerability was exposed. It allowed attackers to extract the TLS certificate private key for any server that was running the affected version of OpenSSL, a popular encryption library. We patched the bug and then as a precaution, quickly reissued private keys and TLS certificates belonging to all of our customers, even though none of our keys were leaked. Cloudflare’s ability to act quickly protected our customers’ data from being exposed.

Heartbleed was a wake-up call. At the time, Cloudflare’s scale was a magnitude smaller. A similar vulnerability at today’s scale would take us weeks, not hours to re-issue all of our customers certificates.

Now, with backup certificates, we don’t need to worry about initiating a mass re-issuance in a small time frame. Instead, customers will already have a certificate that we’ll be able to instantly deploy. Not just that, but the backup certificate will also be wrapped with a different key than the primary certificate, preventing it from being impacted by a key compromise.

Key compromises are one of the main reasons certificates need to be re-issued at scale. But other events can prompt re-issuance as well, including mass revocations by Certificate Authorities.

Mass Revocations from CAs

Today, the Certificate Authority/Browser Forum (CA/B Forum) is the governing body that sets the rules and standards for certificates. One of the Baseline Requirements set by the CA/B Forum states that Certificate Authorities are required to revoke certificates whose keys are at risk of being compromised within 24 hours. For less immediate issues, such as certificate misuse or violation of a CA’s Certificate Policy, certificates need to be revoked within five days. In both scenarios, certificates will be revoked by the CA in a short timeframe and immediate re-issuance of certificates is required.

While mass revocations aren’t commonly initiated by CAs, there have been a few occurrences throughout the last few years. Recently, Let’s Encrypt had to revoke roughly 2.7 million certificates when they found a non-compliance in their implementation of a DCV challenge. In this case, Cloudflare customers were unaffected.

Another time, one of the Certificate Authorities that we use found that they were renewing certificates based on validation tokens that did not comply with the CA/B Forum standards. This caused them to invoke a mass revocation, impacting about five thousand Cloudflare-managed domains. We worked with our customers and the CA to issue new certificates before the revocation, resulting in minimal impact.

We understand that mistakes happen, and we have been lucky enough that as these issues have come up, our engineering teams were able to mitigate quickly so that no customers were impacted. But that’s not enough: our systems need to be future-proof so that a revocation of 45 million certificates will have no impact on our customers. With backup certificates, we’ll be ready for a mass re-issuance, no matter the scale.

To be resilient against mass revocations initiated by our CAs, we are going to issue every backup certificate from a different CA than the primary certificate. This will add a layer of protection if one of our CAs will have to invoke a mass revocation — something that when initiated, is a ticking time bomb.

Challenges when Renewing Certificates

Scale: With great power, comes great responsibility

When the Heartbleed vulnerability was exposed, we had to re-issue about 100,000 certificates. At the time, this wasn’t a challenge for Cloudflare. Now, we are responsible for tens of millions of certificates. Even if our systems are able to handle this scale, we rely on our Certificate Authority partners to be able to handle it as well. In the case of an emergency, we don’t want to rely on systems that we do not control. That’s why it’s important for us to issue the certificates ahead of time, so that during a disaster, all we need to worry about is getting the backup certificates deployed.

Manual intervention for completing DCV

Another challenge that comes with re-issuing certificates is Domain Control Validation (DCV). DCV is a check used to validate the ownership of a domain before a Certificate Authority can issue a certificate for it. When customers onboard to Cloudflare, they can either delegate Cloudflare to be their DNS provider, or they can choose to use Cloudflare as a proxy while maintaining their current DNS provider.

When Cloudflare acts as the DNS provider for a domain, we can add Domain Control Validation (DCV) records on our customer’s behalf. This makes the certificate issuance and renewal process much simpler.

Domains that don’t use Cloudflare as their DNS provider — we call them partial zones — have to rely on other methods for completing DCV. When those domains proxy their traffic through us, we can complete HTTP DCV on their behalf, serving the HTTP DCV token from our Edge. However, customers that want their certificate issued before proxying their traffic need to manually complete DCV. In an event where Cloudflare has to re-issue thousands or millions of certificates, but cannot complete DCV on behalf of the customer, manual intervention will be required. While completing DCV is not an arduous task, it’s not something that we should rely on our customers to do in an emergency, when they have a small time frame, with high risk involved.

This is where backup certificates come into play. From now on, every certificate issuance will fire two orders: one for a certificate from the primary CA and one for the backup certificate. When we can complete the DCV on behalf of the customer, we will do so for both CAs.

Today, we’re only issuing backup certificates for domains that use Cloudflare as an Authoritative DNS provider. In the future, we’ll order backup certificates for partial zones. That means that for backup certificates for which we are unable to complete DCV, we will give customers the corresponding DCV records to get the certificate issued.

Backup Certificates Deployment Plan

We are happy to announce that Cloudflare has started deploying backup certificates on Universal Certificate orders for Free customers that use Cloudflare as an Authoritative DNS provider. We have been slowly ramping up the number of backup certificate orders and in the next few weeks, we expect every new Universal certificate pack order initiated on a Free, Pro, or Biz account to include a backup certificate, wrapped with a different key and issued from a different CA than the primary certificate.

At the end of April we will start issuing backup certificates for our Enterprise customers. If you’re an Enterprise customer and have any questions about backup certificates, please reach out to your Account Team.

Next Up: Backup Certificates for All

Today, Universal certificates make up 72% of the certificates in our pipeline. But we want full coverage! That’s why our team will continue building out our backup certificates pipeline to support Advanced Certificates and SSL for SaaS certificates. In the future, we will also issue backup certificates for certificates that our customers upload themselves, so they can have a backup they can rely on.

In addition, we will continue to improve our pipeline to make the deployment of backup certificates instantaneous — leaving our customers secure and online in an emergency.

At Cloudflare, our mission is to help build a better Internet. With backup certificates, we’re helping build a secure, reliable Internet that’s ready for any disaster. Interested in helping us out? We’re hiring.

Cloudflare for SaaS for All, now Generally Available!

Post Syndicated from Dina Kozlov original https://blog.cloudflare.com/cloudflare-for-saas-for-all-now-generally-available/

Cloudflare for SaaS for All, now Generally Available!

Cloudflare for SaaS for All, now Generally Available!

During Developer Week a few months ago, we opened up the Beta for Cloudflare for SaaS: a one-stop shop for SaaS providers looking to provide fast load times, unparalleled redundancy, and the strongest security to their customers.

Since then, we’ve seen numerous developers integrate with our technology, allowing them to spend their time building out their solution instead of focusing on the burdens of running a fast, secure, and scalable infrastructure — after all, that’s what we’re here for.

Today, we are very excited to announce that Cloudflare for SaaS is generally available, so that every customer, big and small, can use Cloudflare for SaaS to continue scaling and building their SaaS business.

What is Cloudflare for SaaS?

If you’re running a SaaS company, you have customers that are fully reliant on you for your service. That means you’re responsible for keeping their domain fast, secure, and protected. But this isn’t simple. There’s a long checklist you need to get through to put a solution in your customers’ hands:

  • Set up an origin server
  • Encrypt your customers’ traffic
  • Keep your customers online
  • Boost the performance of global customers
  • Support vanity domains
  • Protect against attacks and bots
  • Scale for growth
  • Provide insights and analytics

And on top of that, you need to also focus on building out your solution and your business. As a developer or startup with limited resources, this can delay your product launch by weeks or months.

That’s what we’re here to help with! We have numerous engineering teams whose sole focus is to work on products that take care of each one of these tasks, so you don’t have to!

The Cloudflare solution:

  • Set up an origin server  → Workers
  • Encrypt your customers’ traffic →  SSL for SaaS
  • Keep your customers online → Cloudflare’s global Anycast network
  • Boost the performance of global customers → Argo Smart Routing/Cache
  • Support vanity domains → Custom Hostnames
  • Protect against attacks and bots → WAF and Bot Management
  • Scale for growth → Workers
  • Provide insights and analytics → Custom Hostname Analytics

Pricing, Made for Developers

Starting today, Cloudflare for SaaS is available to purchase on Free, Pro, and Business plans. We wanted to make sure that the pricing made sense for developers. At the time of building, you don’t know how many customers you’ll have, so we wanted to offer flexibility by keeping the pricing as simple as possible: only pay for the customers you use.

Each customer domain using the service is called a Custom Hostname. For each Custom Hostname, we automatically provision a TLS certificate. But not just that!  Beyond the TLS certificate, each of your Custom Hostnames inherits the full suite of Cloudflare products that you set up on your SaaS zone. From Bot Management to Argo Smart Routing, you can extend these add-ons that protect and accelerate your domain to your customers.

Custom Hostnames cost two dollars per month. We will only charge you after each Custom Hostname has been onboarded, adjusted according to when you created it. That means that if you created 10 Custom Hostnames at the start of the month and 10 Custom Hostnames halfway through, at the end of the month you will be billed $30.

This way, you’re only charged for the Custom Hostnames that you provision. It’s also a great incentive to make sure you clean up after your churned customers.

If you’re an Enterprise customer and want to learn more about the benefits that you can from Cloudflare for SaaS, make sure you check out our blog post about the latest developments.

Show us what you’re building!

During the beta alone, we’ve seen incredible projects built out on the platform. We wanted to showcase these developers to show you what’s possible. And even better, some of these have been built on our Workers platform! We’d love to see what you’re working on. Join our Discord channel and showcase your work! Have feature requests for us? Let us know!

mmm.page: Simple Personal Websites

Cloudflare for SaaS for All, now Generally Available!

mmm.page is a drag-and-drop website builder that makes it dead simple to create auto-responsive, collage-like websites: websites with overlapping text, images, GIFs, YouTube videos, Spotify embeds, and (a lot) more. To make it easier, all the standard website tedium — uptime, usability, performance, reliability, responsiveness, SEO, etc. — are handled under the hood so all you have to worry about is adding content and arranging it how you want.

Under their hood is Cloudflare. Cloudflare’s CDN allows both the flexibility of server-side pages as well as the instant loading times of static pages — not to mention an 80% reduction in server costs. Custom Hostnames alone saved months of development time by handling domain names and SSL management (which are otherwise tricky to get perfect and reliable).

They’ve used Workers for increasingly more tasks that would’ve otherwise taken an order of magnitude more time if implemented with their current backend monolith — the ease of deployment and comparatively low cost of Workers is something that keeps them coming back.

The longer-term hope is for pages to be used as a sort of beacon signal, an easy-to-make yet unbounded way to express to others the things you’re interested in, especially for things that aren’t so easily describable or captured in words. They look forward to a world of a ton more DIY micro-sites. Cloudflare has been crucial in taking care of much of the difficult technical plumbing and giving them more time to work on designs and features that get them closer to this hope.

Lightfunnels

Cloudflare for SaaS for All, now Generally Available!

Lightfunnels is a performance driven e-commerce and lead generation platform. It focuses on delivering fast, reliable, and highly converting sales funnels to its users and their customers.

With Cloudflare for SaaS, Lightfunnels allows users to preserve their brand by easily connecting their own domain names with SSL to use on their funnels.

The platform handles large e-commerce traffic volume through Cloudflare Workers. This helps Lightfunnels serve pages from the closest edge to the customer, wherever they are in the world, allowing for blazing fast page load speeds.

Workers also come with a powerful caching API that eliminates a great percentage of back-end trips and reduces the stress on their servers.

“Our aim is to build the best performing e-commerce and lead generation platform on the market. Page load speeds play a significant role in performance. Using Cloudflare for SaaS along with Cloudflare Workers made building a reliable, secure, and fast infrastructure a breeze.”
– Yassir Ennazk, Co-founder & CEO at Lightfunnels

Ventrata

Ventrata is a SaaS multi-channel booking platform for large attractions and tour operators. They power booking sites and B2B booking portals for clients that run on other domains. Cloudflare for SaaS has allowed them to leverage all of Cloudflare’s tools, including Firewall, image caching, Workers, and free TLS certificates on Custom Hostnames, while allowing their clients to keep full control of their brand. Their implementation involved just 4 lines of code without any infrastructure/DevOps help required, which would have been impossible before.

Currently a part of the Beta?

If you were accepted as a part of the Cloudflare for SaaS Beta, you will get a notice next week about migrating to the paid version.  

Help build a better Internet

Want to be a part of the Cloudflare team and work on the products that power Cloudflare for SaaS? We’re hiring!

Introducing SSL/TLS Recommender

Post Syndicated from Suleman Ahmad original https://blog.cloudflare.com/ssl-tls-recommender/

Introducing SSL/TLS Recommender

Introducing SSL/TLS Recommender

Seven years ago, Cloudflare made HTTPS availability for any Internet property easy and free with Universal SSL. At the time, few websites — other than those that processed sensitive data like passwords and credit card information — were using HTTPS because of how difficult it was to set up.

However, as we all started using the Internet for more and more private purposes (communication with loved ones, financial transactions, shopping, healthcare, etc.) the need for encryption became apparent. Tools like Firesheep demonstrated how easily attackers could snoop on people using public Wi-Fi networks at coffee shops and airports. The Snowden revelations showed the ease with which governments could listen in on unencrypted communications at scale. We have seen attempts by browser vendors to increase HTTPS adoption such as the recent announcement by Chromium for loading websites on HTTPS by default. Encryption has become a vital part of the modern Internet, not just to keep your information safe, but to keep you safe.

When it was launched, Universal SSL doubled the number of sites on the Internet using HTTPS. We are building on that with SSL/TLS Recommender, a tool that guides you to stronger configurations for the backend connection from Cloudflare to origin servers. Recommender has been available in the SSL/TLS tab of the Cloudflare dashboard since August 2020 for self-serve customers. Over 500,000 zones are currently signed up. As of today, it is available for all customers!

How Cloudflare connects to origin servers

Cloudflare operates as a reverse proxy between clients (“visitors”) and customers’ web servers (“origins”), so that Cloudflare can protect origin sites from attacks and improve site performance. This happens, in part, because visitor requests to websites proxied by Cloudflare are processed by an “edge” server located in a data center close to the client. The edge server either responds directly back to the visitor, if the requested content is cached, or creates a new request to the origin server to retrieve the content.

Introducing SSL/TLS Recommender

The backend connection to the origin can be made with an unencrypted HTTP connection or with an HTTPS connection where requests and responses are encrypted using the TLS protocol (historically known as SSL). HTTPS is the secured form of HTTP and should be used whenever possible to avoid leaking information or allowing content tampering by third-party entities. The origin server can further authenticate itself by presenting a valid TLS certificate to prevent active monster-in-the-middle attacks. Such a certificate can be obtained from a certificate authority such as Let’s Encrypt or Cloudflare’s Origin CA. Origins can also set up authenticated origin pull, which ensures that any HTTPS requests outside of Cloudflare will not receive a response from your origin.

Cloudflare Tunnel provides an even more secure option for the connection between Cloudflare and origins. With Tunnel, users run a lightweight daemon on their origin servers that proactively establishes secure and private tunnels to the nearest Cloudflare data centers. With this configuration, users can completely lock down their origin servers to only receive requests routed through Cloudflare. While we encourage customers to set up tunnels if feasible, it’s important to encourage origins with more traditional configurations to adopt the strongest possible security posture.

Detecting HTTPS support

You might wonder, why doesn’t Cloudflare always connect to origin servers with a secure TLS connection? To start, some origin servers have no TLS support at all (for example, certain shared hosting providers and even government sites have been slow adopters) and rely on Cloudflare to ensure that the client request is at least encrypted over the Internet from the browser to Cloudflare’s edge.

Then why don’t we simply probe the origin to determine if TLS is supported? It turns out that many sites only partially support HTTPS, making the problem non-trivial. A single customer site can be served from multiple separate origin servers with differing levels of TLS support. For instance, some sites support HTTPS on their landing page but serve certain resources only over unencrypted HTTP. Further, site content can differ when accessed over HTTP versus HTTPS (for example, http://example.com and https://example.com can return different results).

Such content differences can arise due to misconfiguration on the origin server, accidental mistakes by developers when migrating their servers to HTTPS, or can even be intentional depending on the use case.

A study by researchers at Northeastern University, the Max Planck Institute for Informatics, and the University of Maryland highlights reasons for some of these inconsistencies. They found that 1.5% of surveyed sites had at least one page that was unavailable over HTTPS — despite the protocol being supported on other pages — and 3.7% of sites served different content over HTTP versus HTTPS for at least one page. Thus, always using the most secure TLS setting detected on a particular resource could result in unforeseen side effects and usability issues for the entire site.

We wanted to tackle all such issues and maximize the number of TLS connections to origin servers, but without compromising a website’s functionality and performance.

Introducing SSL/TLS Recommender
Content differences on sites when loaded over HTTPS vs HTTP; images taken from https://www.cs.umd.edu/~dml/papers/https_tma20.pdf with author permission

Configuring the SSL/TLS encryption mode

Cloudflare relies on customers to indicate the level of TLS support at their origins via the zone’s SSL/TLS encryption mode. The following SSL/TLS encryption modes can be configured from the Cloudflare dashboard:

  • Off indicates that client requests reaching Cloudflare as well as Cloudflare’s requests to the origin server should only use unencrypted HTTP. This option is never recommended, but is still in use by a handful of customers for legacy reasons or testing.
  • Flexible allows clients to connect to Cloudflare’s edge via HTTPS, but requests to the origin are over HTTP only. This is the most common option for origins that do not support TLS. However, we encourage customers to upgrade their origins to support TLS whenever possible and only use Flexible as a last resort.
  • Full enables encryption for requests to the origin when clients connect via HTTPS, but Cloudflare does not attempt to validate the certificate. This is useful for origins that have a self-signed or otherwise invalid certificate at the origin, but leaves open the possibility for an active attacker to impersonate the origin server with a fake certificate. Client HTTP requests result in HTTP requests to the origin.
  • Full (strict) indicates that Cloudflare should validate the origin certificate to fully secure the connection. The origin certificate can either be issued by a public CA or by Cloudflare Origin CA. HTTP requests from clients result in HTTP requests to the origin, exactly the same as in Full mode. We strongly recommend Full (strict) over weaker options if supported by the origin.
  • Strict (SSL-Only Origin Pull) causes all traffic to the origin to go over HTTPS, even if the client request was HTTP. This differs from Full (strict) in that HTTP client requests will result in an HTTPS request to the origin, not HTTP. Most customers do not need to use this option, and it is available only to Enterprise customers. The preferred way to ensure that no HTTP requests reach your origin is to enable Always Use HTTPS in conjunction with Full or Full (strict) to redirect visitor HTTP requests to the HTTPS version of the content.
Introducing SSL/TLS Recommender
SSL/TLS encryption modes determine how Cloudflare connects to origins

The SSL/TLS encryption mode is a zone-wide setting, meaning that Cloudflare applies the same policy to all subdomains and resources. If required, you can configure this setting more granularly via Page Rules. Misconfiguring this setting can make site resources unavailable. For instance, suppose your website loads certain assets from an HTTP-only subdomain. If you set your zone to Full or Full (strict), you might make these assets unavailable for visitors that request the content over HTTPS, since the HTTP-only subdomain lacks HTTPS support.

Importance of secure origin connections

When an end-user visits a site proxied by Cloudflare, there are two connections to consider: the front-end connection between the visitor and Cloudflare and the back-end connection between Cloudflare and the customer origin server. The front-end connection typically presents the largest attack surface (for example, think of the classic example of an attacker snooping on a coffee shop’s Wi-Fi network), but securing the back-end connection is equally important. While all SSL/TLS encryption modes (except Off) secure the front-end connection, less secure modes leave open the possibility of malicious activity on the backend.

Consider a zone set to Flexible where the origin is connected to the Internet via an untrustworthy ISP. In this case, spyware deployed by the customer’s ISP in an on-path middlebox could inspect the plaintext traffic from Cloudflare to the origin server, potentially resulting in privacy violations or leaks of confidential information. Upgrading the zone to Full or a stronger mode to encrypt traffic to the ISP would help prevent this basic form of snooping.

Similarly, consider a zone set to Full where the origin server is hosted in a shared hosting provider facility. An attacker colocated in the same facility could generate a fake certificate for the origin (since the certificate isn’t validated for Full) and deploy an attack technique such as ARP spoofing to direct traffic intended for the origin server to an attacker-owned machine instead. The attacker could then leverage this setup to inspect and filter traffic intended for the origin, resulting in site breakage or content unavailability. The attacker could even inject malicious JavaScript into the response served to the visitor to carry out other nefarious goals. Deploying a valid Cloudflare-trusted certificate on the origin and configuring the zone to use Full (strict) would prevent Cloudflare from trusting the attacker’s fake certificate in this scenario, preventing the hijack.

Since a secure backend only improves your website security, we strongly encourage setting your zone to the highest possible SSL/TLS encryption mode whenever possible.

Balancing functionality and security

When Universal SSL was launched, Cloudflare’s goal was to get as many sites away from the status quo of HTTP as possible. To accomplish this, Cloudflare provisioned TLS certificates for all customer domains to secure the connection between the browser and the edge. Customer sites that did not already have TLS support were defaulted to Flexible, to preserve existing site functionality. Although Flexible is not recommended for most zones, we continue to support this option as some Cloudflare customers still rely on it for origins that do not yet support TLS. Disabling this option would make these sites unavailable. Currently, the default option for newly onboarded zones is Full if we detect a TLS certificate on the origin zone, and Flexible otherwise.

Further, the SSL/TLS encryption mode configured at the time of zone sign-up can become suboptimal as a site evolves. For example, a zone might switch to a hosting provider that supports origin certificate installation. An origin server that is able to serve all content over TLS should at least be on Full. An origin server that has a valid TLS certificate installed should use Full (strict) to ensure that communication between Cloudflare and the origin server is not susceptible to monster-in-the-middle attacks.

The Research team combined lessons from academia and our engineering efforts to make encryption easy, while ensuring the highest level of security possible for our customers. Because of that goal, we’re proud to introduce SSL/TLS Recommender.

SSL/TLS Recommender

Cloudflare’s mission is to help build a better Internet, and that includes ensuring that requests from visitors to our customers’ sites are as secure as possible. To that end, we began by asking ourselves the following question: how can we detect when a customer is able to use a more secure SSL/TLS encryption mode without impacting site functionality?

To answer this question, we built the SSL/TLS Recommender. Customers can enable Recommender for a zone via the SSL/TLS tab of the Cloudflare dashboard. Using a zone’s currently configured SSL/TLS option as the baseline for expected site functionality, the Recommender performs a series of checks to determine if an upgrade is possible. If so, we email the zone owner with the recommendation. If a zone is currently misconfigured — for example, an HTTP-only origin configured on Full — Recommender will not recommend a downgrade.

Introducing SSL/TLS Recommender

The checks that Recommender runs are determined by the site’s currently configured SSL/TLS option.

The simplest check is to determine if a customer can upgrade from Full to Full (strict). In this case, all site resources are already served over HTTPS, so the check comprises a few simple tests of the validity of the TLS certificate for the domain and all subdomains (which can be on separate origin servers).

The check to determine if a customer can upgrade from Off or Flexible to Full is more complex. A site can be upgraded if all resources on the site are available over HTTPS and the content matches when served over HTTP versus HTTPS. Recommender carries out this check as follows:

  • Crawl customer sites to collect links. For large sites where it is impractical to scan every link, Recommender tests only a subset of links (up to some threshold), leading to a trade-off between performance and potential false positives. Similarly, for sites where the crawl turns up an insufficient number of links, we augment our results with a sample of links from recent visitors requests to the zone to provide a high-confidence recommendation. The crawler uses the user agent Cloudflare-SSLDetector and has been added to Cloudflare’s list of known good bots. Similar to other Cloudflare crawlers, Recommender ignores robots.txt (except for rules explicitly targeting the crawler’s user agent) to avoid negatively impacting the accuracy of the recommendation.
  • Download the content of each link over both HTTP and HTTPS. Recommender makes only idempotent GET requests when scanning origin servers to avoid modifying server resource state.
  • Run a content similarity algorithm to determine if the content matches. The algorithm is adapted from a research paper called “A Deeper Look at Web Content Availability and Consistency over HTTP/S” (TMA Conference 2020) and is designed to provide an accurate similarity score even for sites with dynamic content.

Recommender is conservative with recommendations, erring on the side of maintaining current site functionality rather than risking breakage and usability issues. If a zone is non-functional, the zone owner blocks all types of bots, or if misconfigured SSL-specific Page Rules are applied to the zone, then Recommender will not be able to complete its scans and provide a recommendation. Therefore, it is not intended to resolve issues with website or domain functionality, but rather maximize your zone’s security when possible.

Please send questions and feedback to [email protected]. We’re excited to continue this line of work to improve the security of customer origins!

Mentions

While this work is led by the Research team, we have been extremely privileged to get support from all across the company!

Special thanks to the incredible team of interns that contributed to SSL/TLS Recommender. Suleman Ahmad (now full-time), Talha Paracha, and Ananya Ghose built the current iteration of the project and Matthew Bernhard helped to lay the groundwork in a previous iteration of the project.

Staging TLS Certificate: Make every deployment a safe deployment

Post Syndicated from Dina Kozlov original https://blog.cloudflare.com/staging-tls-certificate-every-deployment-safe-deployment/

Staging TLS Certificate: Make every deployment a safe deployment

Staging TLS Certificate: Make every deployment a safe deployment

We are excited to announce that Enterprise customers now have the ability to test custom uploaded certificates in a staging environment before pushing them to production.

With great power comes great responsibility

If you’re running a website or the API that’s behind a popular app, you know your users have high expectations: it can’t just be up and running; it also has to be fast and secure. One of the easiest and most standardized ways to secure connections is with the TLS protocol. To do that, you need to acquire a TLS certificate for your domain.

One way to get a certificate is by using a CDN provider, like Cloudflare. We make the process really easy by issuing certificates on your behalf. Not just that, but when your certificate is getting closer to its expiration date, we are responsible for re-issuing it. But, if you don’t want Cloudflare to issue the certificate on your behalf and want to obtain the certificate yourself, you can do so. You can either keep control of your private key, or generate a Certificate Signing Request (CSR) through Cloudflare, so we maintain the private key, but you can still use the certificate authority (CA) of your choice for the certificate. Once you get your certificate, you upload it to Cloudflare and voilà — your site is secure.

One of the downsides of obtaining your own certificate is that you’re in charge of its renewal, which comes with a great deal of responsibility. You have to ensure that any renewed certificate  will not cause TLS errors, causing your property to be unreachable by your users.

Now, you’re probably wondering, why is this so risky? What could go wrong?

It’s possible that when you renew a certificate, you forget to include one of your subdomains in the certificate. Another reason why your clients might see failures when you upload the new certificate is that some of those clients are pinning the old certificate.

The problem with pinning certificates

Certificate pinning allows Internet application owners to say “trust this certificate and no other” by pinning the certificate or public key to their service, or even to client devices. While this was originally intended to tighten security, certificate pinning has created many problems. We have seen customers shoot themselves in the foot with certificate pinning numerous times. There are a lot of things that could go wrong: you could pin the wrong certificate, or configure the wrong settings, which will bring your service down. It’s possible that you rely on a CDN for your certificate renewal and forgot to update your pin — again, blocking access to your service in the process. Alternatively, you can pin certificates to clients so that they refuse connections from servers that don’t have the same certificate. But when it comes to renewing that certificate, you have to make sure that your clients have the updated certificate, or they won’t be able to access your server. Instead, you can use tools like Cloudflare’s Certificate Transparency Monitoring which notifies you when certificates are being issued for your domain.

But, some of our customers do rely on this behavior. So for them, switching to a new certificate is a big change — one that can bring down their whole application. For this reason, they need to be able to test the new certificate to identify any problems that may occur before their customers see it.

A staging environment for certificate deployments

When it comes to your traffic, there are things you can’t predict. You can’t control if your customer’s browser is having a bad day, or if some ISP is having a network outage. When it comes to certificate deployment, the last thing you want is to be surprised. Imagine pushing out a new certificate, and realizing you’ve uploaded the wrong one only after customers complain they’ve lost access; or that you never updated your pin to your new certificate to begin with. Mistakes happen, but this type of outage can cause a lot of pain and lose you a lot of money and trust. The good news is that this is preventable.

We are giving customers the ability to find these problems before they’re encountered by real users. We’re doing this by giving customers the ability to test certificate deployment changes against a pair of staging IPs.

Imagine uploading a new certificate, finding any related problems, and fixing them in a way that doesn’t impact production traffic. That’s exactly what Staging Certificates allows you to do!

You can go to the Staging Certificates section under the SSL/TLS tab in the Cloudflare dashboard and upload a new certificate to our staging network. The staging network will replicate your production environment but will only be accessible through the Staging IPs.

Staging TLS Certificate: Make every deployment a safe deployment

Once you upload your certificate, you can make `curl` requests against the staging IPs to verify that it’s being served and that it covers all the hostnames that you need it to. If you’ve decided to pin your previous certificate, the staging environment helps you verify that your pins have been updated correctly and that TLS termination is successful.

Once you’re confident in your tests, you can push the certificate out to production.

Oh no, something went wrong

Mistakes happen. It’s possible that you found one client device whose pin you forgot to update. In that case, you can disable the certificate to quickly mitigate the problem by rolling back to the certificate that you were last serving.

Staging TLS Certificate: Make every deployment a safe deployment

What if you realize that this is a bigger issue, and you need more time to test? You can push the disabled certificate back to the staging environment, and when you’ve verified everything works correctly, push it back to production.

Staging changes: We’re just getting started

We want to de-risk every change you make. Staging your custom uploaded certificates is a start, but it doesn’t end there. In the future, we’ll allow you to stage certificate renewals for certificates issued through Cloudflare. We’re also planning to give customers the ability to test TLS configuration changes like minimum TLS or cipher suite settings.

If you’re interested in staying aware of these future developments, or you have some settings that you want to test in staging, reach out to your Account team and let them know!

Ready to test your next certificate deployment?

This feature is currently in Beta and available to Enterprise customers. If you want to use it, reach out to your Account team to get it enabled.

What’s new with Cloudflare for SaaS?

Post Syndicated from Dina Kozlov original https://blog.cloudflare.com/whats-new-with-cloudflare-for-saas/

What’s new with Cloudflare for SaaS?

What’s new with Cloudflare for SaaS?

This past April, we announced the Cloudflare for SaaS Beta which makes our SSL for SaaS product available to everyone. This allows any customer — from first-time developers to large enterprises — to use Cloudflare for SaaS to extend our full product suite to their own customers. SSL for SaaS is the subset of Cloudflare for SaaS features that focus on a customer’s Public Key Infrastructure (PKI) needs.

Today, we’re excited to announce all the customizations that our team has been working on for our Enterprise customers — for both Cloudflare for SaaS and SSL for SaaS.

Let’s start with the basics — the common SaaS setup

If you’re running a SaaS company, your solution might exist as a subdomain of your SaaS website, e.g. template.<mysaas>.com, but ideally, your solution would allow the customer to use their own vanity hostname for it, such as example.com.

The most common way to begin using a SaaS company’s service is to point a CNAME DNS record to the subdomain that the SaaS provider has created for your application. This ensures traffic gets to the right place, and it allows the SaaS provider to make infrastructure changes without involving your end customers.

What’s new with Cloudflare for SaaS?

We kept this in mind when we built our SSL for SaaS a few years ago. SSL for SaaS takes away the burden of certificate issuance and management from the SaaS provider by proxying traffic through Cloudflare’s edge. All the SaaS provider needs to do is onboard their zone to Cloudflare and ask their end customers to create a CNAME to the SaaS zone — something they were already doing.

The big benefit of giving your customers a CNAME record (instead of a fixed IP address) is that it gives you, the SaaS provider, more flexibility and control. It allows you to seamlessly change the IP address of your server in the background. For example, if your IP gets blocked by ISP providers, you can update that address on your customers’ behalf with a CNAME record. With a fixed A record, you rely on each of your customers to make a change.

While the CNAME record works great for most customers, some came back and wanted to bypass the limitation that CNAME records present. RFC 1912 states that CNAME records cannot coexist with other DNS records, so in most cases, you cannot have a CNAME at the root of your domain, e.g. example.com. Instead, the CNAME needs to exist at the subdomain level, i.e. www.example.com. Some DNS providers (including Cloudflare) bypass this restriction through a method called CNAME flattening.

Since SaaS providers have no control over the DNS provider that their customers are using, the feedback they got from their customers was that they wanted to use the apex of their zone and not the subdomain. So when our SaaS customers came back asking us for a solution, we delivered. We call it Apex Proxying.

Apex Proxying

For our SaaS customers who want to allow their customers to proxy their apex to their zone, regardless of which DNS provider they are using, we give them the option of Apex Proxying. Apex Proxying is an SSL for SaaS feature that gives SaaS providers a pair of IP addresses to provide to their customers when CNAME records do not work for them.

Cloudflare starts by allocating a dedicated set of IPs for the SaaS provider. The SaaS provider then gives their customers these IPs that they can add as A or AAAA DNS records, allowing them to proxy traffic directly from the apex of their zone.

While this works for most, some of our customers want more flexibility. They want to have multiple IPs that they can change, or they want to assign different sets of customers to different buckets of IPs. For those customers, we give them the option to bring their own IP range, so they control the IP allocation for their application.

What’s new with Cloudflare for SaaS?

Bring Your Own IPs

Last year, we announced Bring Your Own IP (BYOIP), which allows customers to bring their own IP range for Cloudflare to announce at our edge. One of the benefits of BYOIP is that it allows SaaS customers to allocate that range to their account and then, instead of having a few IPs that their customers can point to, they can distribute all the IPs in their range.

What’s new with Cloudflare for SaaS?

SaaS customers often require granular control of how their IPs are allocated to different zones that belong to different customers. With 256 IPs to use, you have the flexibility to either group customers together or to give them dedicated IPs. It’s up to you!

While we’re on the topic of grouping customers, let’s talk about how you might want to do this when sending traffic to your origin.

Custom Origin Support

When setting up Cloudflare for SaaS, you indicate your fallback origin, which defines the origin that all of your Custom Hostnames are routed to. This origin can be defined by an IP address or point to a load balancer defined in the zone. However, you might not want to route all customers to the same origin. Instead, you want to route different customers (or custom hostnames) to different origins — either because you want to group customers together or to help you scale the origins supporting your application.

Our Enterprise customers can now choose a custom origin that is not the default fallback origin for any of their Custom Hostnames. Traditionally, this has been done by emailing your account manager and requesting custom logic at Cloudflare’s edge, a very cumbersome and outdated practice. But now, customers can easily indicate this in the UI or in their API requests.

Wildcard Support

Oftentimes, SaaS providers have customers that don’t just want their domain to stay protected and encrypted, but also the subdomains that fall under it.

We wanted to give our Enterprise customers the flexibility to extend this benefit to their end customers by offering wildcard support for Custom Hostnames.

Wildcard Custom Hostnames extend the Custom Hostname’s configuration from a specific hostname — e.g. “blog.example.com” — to the next level of subdomains of that hostname, e.g. “*.blog.example.com”.

To create a Custom Hostname with a wildcard, you can either indicate Enable wildcard support when creating a Custom Hostname in the Cloudflare dashboard or when you’re creating a Custom Hostname through the API, indicate wildcard: “true”.

What’s new with Cloudflare for SaaS?

Now let’s switch gears to TLS certificate management and the improvements our team has been working on.

TLS Management for All

SSL for SaaS was built to reduce the burden of certificate management for SaaS providers. The initial functionality was meant to serve most customers and their need to issue, maintain, and renew certificates on their customers’ behalf. But one size does not fit all, and some of our customers have more specific needs for their certificate management — and we want to make sure we accommodate them.

CSR Support/Custom certs

One of the superpowers of SSL for SaaS is that it allows Cloudflare to manage all the certificate issuance and renewals on behalf of our customers and their customers. However, some customers want to allow their end customers to upload their own certificates.

For example, a bank may only trust certain certificate authorities (CAs) for their certificate issuance. Alternatively, the SaaS provider may have initially built out TLS support for their customers and now their customers expect that functionality to be available. Regardless of the reasoning, we have given our customers a few options that satisfy these requirements.

For customers who want to maintain control over their TLS private keys or give their customers the flexibility to use their certification authority (CA) of choice, we allow the SaaS provider to upload their customer’s certificate.

If you are a SaaS provider and one of your customers does not allow third parties to generate keys on their behalf, then you want to allow that customer to upload their own certificate. Cloudflare allows SaaS providers to upload their customers’ certificates to any of their custom hostnames — in just one API call!

Some SaaS providers never want a person to see private key material, but want to be able to use the CA of their choice. They can do so by generating a Certificate Signing Request (CSR) for their Custom Hostnames, and then either use those CSRs themselves to order certificates for their customers or relay the CSRs to their customers so that they can provision their own certificates. In either case, the SaaS provider is able to then upload the certificate for the Custom Hostname after the certificate has been issued from their customer’s CA for use at Cloudflare’s edge.

Custom Metadata

For our customers who need to customize their configuration to handle specific rules for their customer’s domains, they can do so by using Custom Metadata and Workers.

By adding metadata to an individual custom hostname and then deploying a Worker to read the data, you can use the Worker to customize per-hostname behavior.

Some customers use this functionality to add a customer_id field to each custom hostname that they then send in a request header to their origin. Another way to use this is to set headers like HTTP Strict Transport Security (HSTS) on a per-customer basis.

Saving the best for last: Analytics!

Tomorrow, we have a very special announcement about how you can now get more visibility into your customers’ traffic and — more importantly —  how you can share this information back to them.

Interested? Reach out!

If you’re an Enterprise customer, and you’re interested in any of these features, reach out to your account team to get access today!

Round 2 post-quantum TLS is now supported in AWS KMS

Post Syndicated from Alex Weibel original https://aws.amazon.com/blogs/security/round-2-post-quantum-tls-is-now-supported-in-aws-kms/

AWS Key Management Service (AWS KMS) now supports three new hybrid post-quantum key exchange algorithms for the Transport Layer Security (TLS) 1.2 encryption protocol that’s used when connecting to AWS KMS API endpoints. These new hybrid post-quantum algorithms combine the proven security of a classical key exchange with the potential quantum-safe properties of new post-quantum key exchanges undergoing evaluation for standardization. The fastest of these algorithms adds approximately 0.3 milliseconds of overheard compared to a classical TLS handshake. The new post-quantum key exchange algorithms added are Round 2 versions of Kyber, Bit Flipping Key Encapsulation (BIKE), and Supersingular Isogeny Key Encapsulation (SIKE). Each organization has submitted their algorithms to the National Institute of Standards and Technology (NIST) as part of NIST’s post-quantum cryptography standardization process. This process spans several rounds of evaluation over multiple years, and is likely to continue beyond 2021.

In our previous hybrid post-quantum TLS blog post, we announced that AWS KMS had launched hybrid post-quantum TLS 1.2 with Round 1 versions of BIKE and SIKE. The Round 1 post-quantum algorithms are still supported by AWS KMS, but at a lower priority than the Round 2 algorithms. You can choose to upgrade your client to enable negotiation of Round 2 algorithms.

Why post-quantum TLS is important

A large-scale quantum computer would be able to break the current public-key cryptography that’s used for key exchange in classical TLS connections. While a large-scale quantum computer isn’t available today, it’s still important to think about and plan for your long-term security needs. TLS traffic using classical algorithms recorded today could be decrypted by a large-scale quantum computer in the future. If you’re developing applications that rely on the long-term confidentiality of data passed over a TLS connection, you should consider a plan to migrate to post-quantum cryptography before the lifespan of the sensitivity of your data would be susceptible to an unauthorized user with a large-scale quantum computer. As an example, this means that if you believe that a large-scale quantum computer is 25 years away, and your data must be secure for 20 years, you should migrate to post-quantum schemes within the next 5 years. AWS is working to prepare for this future, and we want you to be prepared too.

We’re offering this feature now instead of waiting for standardization efforts to be complete so you have a way to measure the potential performance impact to your applications. Offering this feature now also gives you the protection afforded by the proposed post-quantum schemes today. While we believe that the use of this feature raises the already high security bar for connecting to AWS KMS endpoints, these new cipher suites will impact bandwidth utilization and latency. However, using these new algorithms could also create connection failures for intermediate systems that proxy TLS connections. We’d like to get feedback from you on the effectiveness of our implementation or any issues found so we can improve it over time.

Hybrid post-quantum TLS 1.2

Hybrid post-quantum TLS is a feature that provides the security protections of both the classical and post-quantum key exchange algorithms in a single TLS handshake. Figure 1 shows the differences in the connection secret derivation process between classical and hybrid post-quantum TLS 1.2. Hybrid post-quantum TLS 1.2 has three major differences from classical TLS 1.2:

  • The negotiated post-quantum key is appended to the ECDHE key before being used as the hash-based message authentication code (HMAC) key.
  • The text hybrid in its ASCII representation is prepended to the beginning of the HMAC message.
  • The entire client key exchange message from the TLS handshake is appended to the end of the HMAC message.
Figure 1: Differences in the connection secret derivation process between classical and hybrid post-quantum TLS 1.2

Figure 1: Differences in the connection secret derivation process between classical and hybrid post-quantum TLS 1.2

Some background on post-quantum TLS

Today, all requests to AWS KMS use TLS with key exchange algorithms that provide perfect forward secrecy and use one of the following classical schemes:

While existing FFDHE and ECDHE schemes use perfect forward secrecy to protect against the compromise of the server’s long-term secret key, these schemes don’t protect against large-scale quantum computers. In the future, a sufficiently capable large-scale quantum computer could run Shor’s Algorithm to recover the TLS session key of a recorded classical session, and thereby gain access to the data inside. Using a post-quantum key exchange algorithm during the TLS handshake protects against attacks from a large-scale quantum computer.

The possibility of large-scale quantum computing has spurred the development of new quantum-resistant cryptographic algorithms. NIST has started the process of standardizing post-quantum key encapsulation mechanisms (KEMs). A KEM is a type of key exchange that’s used to establish a shared symmetric key. AWS has chosen three NIST KEM submissions to adopt in our post-quantum efforts:

Hybrid mode ensures that the negotiated key is as strong as the weakest key agreement scheme. If one of the schemes is broken, the communications remain confidential. The Internet Engineering Task Force (IETF) Hybrid Post-Quantum Key Encapsulation Methods for Transport Layer Security 1.2 draft describes how to combine post-quantum KEMs with ECDHE to create new cipher suites for TLS 1.2.

These cipher suites use a hybrid key exchange that performs two independent key exchanges during the TLS handshake. The key exchange then cryptographically combines the keys from each into a single TLS session key. This strategy combines the proven security of a classical key exchange with the potential quantum-safe properties of new post-quantum key exchanges being analyzed by NIST.

The effect of hybrid post-quantum TLS on performance

Post-quantum cipher suites have a different performance profile and bandwidth usage from traditional cipher suites. AWS has measured bandwidth and latency across 2,000 TLS handshakes between an Amazon Elastic Compute Cloud (Amazon EC2) C5n.4xlarge client and the public AWS KMS endpoint, which were both in the us-west-2 Region. Your own performance characteristics might differ, and will depend on your environment, including your:

  • Hardware–CPU speed and number of cores.
  • Existing workloads–how often you call AWS KMS and what other work your application performs.
  • Network–location and capacity.

The following graphs and table show latency measurements performed by AWS for all newly supported Round 2 post-quantum algorithms, in addition to the classical ECDHE key exchange algorithm currently used by most customers.

Figure 2 shows the latency differences of all hybrid post-quantum algorithms compared with classical ECDHE alone, and shows that compared to ECDHE alone, SIKE adds approximately 101 milliseconds of overhead, BIKE adds approximately 9.5 milliseconds of overhead, and Kyber adds approximately 0.3 milliseconds of overhead.
 

Figure 2: TLS handshake latency at varying percentiles for four key exchange algorithms

Figure 2: TLS handshake latency at varying percentiles for four key exchange algorithms

Figure 3 shows the latency differences between ECDHE with Kyber, and ECDHE alone. The addition of Kyber adds approximately 0.3 milliseconds of overhead.
 

Figure 3: TLS handshake latency at varying percentiles, with only top two performing key exchange algorithms

Figure 3: TLS handshake latency at varying percentiles, with only top two performing key exchange algorithms

The following table shows the total amount of data (in bytes) needed to complete the TLS handshake for each cipher suite, the average latency, and latency at varying percentiles. All measurements were gathered from 2,000 TLS handshakes. The time was measured on the client from the start of the handshake until the handshake was completed, and includes all network transfer time. All connections used RSA authentication with a 2048-bit key, and ECDHE used the secp256r1 curve. All hybrid post-quantum tests used the NIST Round 2 versions. The Kyber test used the Kyber-512 parameter, the BIKE test used the BIKE-1 Level 1 parameter, and the SIKE test used the SIKEp434 parameter.

Item Bandwidth
(bytes)		 Total
handshakes		 Average
(ms)		 p0
(ms)		 p50
(ms)		 p90
(ms)		 p99
(ms)
ECDHE (classic) 3,574 2,000 3.08 2.07 3.02 3.95 4.71
ECDHE + Kyber R2 5,898 2,000 3.36 2.38 3.17 4.28 5.35
ECDHE + BIKE R2 12,456 2,000 14.91 11.59 14.16 18.27 23.58
ECDHE + SIKE R2 4,628 2,000 112.40 103.22 108.87 126.80 146.56

By default, the AWS SDK client performs a TLS handshake once to set up a new TLS connection, and then reuses that TLS connection for multiple requests. This means that the increased cost of a hybrid post-quantum TLS handshake is amortized over multiple requests sent over the TLS connection. You should take the amortization into account when evaluating the overall additional cost of using post-quantum algorithms; otherwise performance data could be skewed.

AWS KMS has chosen Kyber Round 2 to be KMS’s highest prioritized post-quantum algorithm, with BIKE Round 2, and SIKE Round 2 next in priority order for post-quantum algorithms. This is because Kyber’s performance is closest to the classical ECDHE performance that most AWS KMS customers are using today and are accustomed to.

How to use hybrid post-quantum cipher suites

To use the post-quantum cipher suites with AWS KMS, you need the preview release of the AWS Common Runtime (CRT) HTTP client for the AWS SDK for Java 2.x. Also, you will need to configure the AWS CRT HTTP client to use the s2n post-quantum hybrid cipher suites. Post-quantum TLS for AWS KMS is available in all AWS Regions except for AWS GovCloud (US-East), AWS GovCloud (US-West), AWS China (Beijing) Region operated by Beijing Sinnet Technology Co. Ltd (“Sinnet”), and AWS China (Ningxia) Region operated by Ningxia Western Cloud Data Technology Co. Ltd. (“NWCD”). Since NIST has not yet standardized post-quantum cryptography, connections that require Federal Information Processing Standards (FIPS) compliance cannot use the hybrid key exchange. For example, kms.<region>.amazonaws.com supports the use of post-quantum cipher suites, while kms-fips.<region>.amazonaws.com does not.

  1. If you’re using the AWS SDK for Java 2.x, you must add the preview release of the AWS Common Runtime client to your Maven dependencies. 
    <dependency>
    <groupId>software.amazon.awssdk</groupId>
    <artifactId>aws-crt-client</artifactId>
    <version>2.14.13-PREVIEW</version>
</dependency>

  2. You then must configure the new SDK and cipher suite in the existing initialization code of your application: 
    if(!TLS_CIPHER_PREF_KMS_PQ_TLSv1_0_2020_07.isSupported()){
    throw new RuntimeException("Post Quantum Ciphers not supported on this Platform");
}

SdkAsyncHttpClient awsCrtHttpClient = AwsCrtAsyncHttpClient.builder()
          .tlsCipherPreference(TLS_CIPHER_PREF_KMS_PQ_TLSv1_0_2020_07)
          .build();
          
KmsAsyncClient kms = KmsAsyncClient.builder()
         .httpClient(awsCrtHttpClient)
         .build();
         
ListKeysResponse response = kms.listKeys().get();

Now, all connections made to AWS KMS in supported Regions will use the new hybrid post-quantum cipher suites! To see a complete example of everything set up, check out the example application here.

Things to try

Here are some ideas about how to use this post-quantum-enabled client:

  • Run load tests and benchmarks. These new cipher suites perform differently than traditional key exchange algorithms. You might need to adjust your connection timeouts to allow for the longer handshake times or, if you’re running inside an AWS Lambda function, extend the execution timeout setting.
  • Try connecting from different locations. Depending on the network path your request takes, you might discover that intermediate hosts, proxies, or firewalls with deep packet inspection (DPI) block the request. This could be due to the new cipher suites in the ClientHello or the larger key exchange messages. If this is the case, you might need to work with your security team or IT administrators to update the relevant configuration to unblock the new TLS cipher suites. We’d like to hear from you about how your infrastructure interacts with this new variant of TLS traffic. If you have questions or feedback, please start a new thread on the AWS KMS discussion forum.

Conclusion

In this blog post, I announced support for Round 2 hybrid post-quantum algorithms in AWS KMS, and showed you how to begin experimenting with hybrid post-quantum key exchange algorithms for TLS when connecting to AWS KMS endpoints.

More info

If you’d like to learn more about post-quantum cryptography check out:

If you have feedback about this post, submit comments in the Comments section below.

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Author

Alex Weibel

Alex is a Senior Software Engineer on the AWS Crypto Algorithms team. He’s one of the maintainers for Amazon’s TLS Library s2n. Previously, Alex worked on TLS termination and request proxying for S3 and the Elastic Load Balancing Service developing new features for customers. Alex holds a Bachelor of Science degree in Computer Science from the University of Texas at Austin.