Tag Archives: Browser Isolation

Click Here! (safely): Automagical Browser Isolation for potentially unsafe links in email

Post Syndicated from Joao Sousa Botto original https://blog.cloudflare.com/safe-email-links/

Click Here! (safely): Automagical Browser Isolation for potentially unsafe links in email

Click Here! (safely): Automagical Browser Isolation for potentially unsafe links in email

We’re often told not to click on ‘odd’ links in email, but what choice do we really have? With the volume of emails and the myriad of SaaS products that companies use, it’s inevitable that employees find it almost impossible to distinguish a good link before clicking on it. And that’s before attackers go about making links harder to inspect and hiding their URLs behind tempting “Confirm” and “Unsubscribe” buttons.

We need to let end users click on links and have a safety net for when they unwittingly click on something malicious — let’s be honest, it’s bound to happen even if you do it by mistake. That safety net is Cloudflare’s Email Link Isolation.

With Email Link Isolation, when a user clicks on a suspicious link — one that email security hasn’t identified as ‘bad’, but is still not 100% sure it’s ‘good’ — they won’t immediately be taken to that website. Instead, the user first sees an interstitial page recommending extra caution with the website they’ll visit, especially if asked for passwords or personal details.

Click Here! (safely): Automagical Browser Isolation for potentially unsafe links in email

From there, one may choose to not visit the webpage or to proceed and open it in a remote isolated browser that runs on Cloudflare’s global network and not on the user’s local machine. This helps protect the user and the company.

The user experience in our isolated browser is virtually indistinguishable from using one’s local browser (we’ll talk about why below), but untrusted and potentially malicious payloads will execute away from the user’s computer and your corporate network.

In summary, this solution:

  • Keeps users alert to prevent credential theft and account takeover
  • Automatically blocks dangerous downloads
  • Prevents malicious scripts from executing on the user’s device
  • Protects against zero-day exploits on the browser

How can I try it

Area 1 is Cloudflare’s email security solution. It protects organizations from the full range of email attack types (URLs, payloads, BEC), vectors (email, web, network), and attack channels (external, internal, trusted partners) by enforcing multiple layers of protection before, during, and after the email hits the inbox. Today it adds Email Link Isolation to the protections it offers.

If you are a Cloudflare Area 1 customer you can request access to the Email Link Isolation beta today. We have had Email Link Isolation deployed to all Cloudflare employees for the last four weeks and are ready to start onboarding customers.

During the beta it will be available for free on all plans. After the beta it will still be included at no extra cost with our PhishGuard plan.

Under the hood

To create Email Link Isolation we used a few ingredients that are quite special to Cloudflare. It may seem complicated and, in a sense, the protection is complex, but we designed this so that the user experience is fast, safe, and with clear options on how to proceed.

1. Find potentially unsafe domains

First, we have created a constantly updating list of domains that the Cloudflare’s DNS resolver recently saw for the first time, or that are somehow potentially unsafe (leveraging classifiers from the Cloudflare Gateway and other products). These are domains that would be too disruptive for the organization to block outright, but that should still be navigated with extra caution.

For example, people acquire domains and create new businesses every day. There’s nothing wrong with that – quite the opposite. However, attackers often set up or acquire websites serving legitimate content and, days or weeks later, send a link to intended targets. The emails flow through as benign and the attacker weaponizes the website when emails are already sitting on people’s inboxes. Blocking all emails with links to new websites would cause users to surely miss important communications, and delivering the emails while making links safe to click on is a much better suited approach.

There is also hosting infrastructure from large cloud providers, such as Microsoft or Google, that prevent crawling and scanning. These are used on our day-to-day business, but attackers may deploy malicious content there. You wouldn’t want to fully block emails with links to Microsoft SharePoint, for example, but it’s certainly safer to use Email Link Isolation on them if they link to outside your organization.

Attackers are constantly experimenting with new ways of looking legitimate to their targets, and that’s why relying on the early signals that Cloudflare sees makes such a big difference.

The second ingredient we want to highlight is that, as Cloudflare Area 1 processes and inspects emails for security concerns, it also checks the domain of every link against the suspicious list. If an email contains a link to a suspicious domain, Cloudflare Area 1 automatically changes it (rewrites) so that the interstitial page is shown, and the link opens with Cloudflare Browser Isolation by default.

Note: Rewriting email links is only possible when emails are processed inline, which is one of the options for deploying Area 1. One of the big disadvantages of any email security solution deployed as API-only is that closing this last mile gap through link rewriting isn’t a possibility.

3. Opens remotely but feels local

When a user clicks on one of these rewritten links, instead of directly accessing a potential threat, our systems will first check their current classification (benign, suspicious, malicious). Then, if it’s malicious, the user will be blocked from continuing to the website and see an interstitial page informing them why. No further action is required.

If the link is suspicious, the user is offered the option to open it in an isolated browser. What happens next? The link is opened with Cloudflare Browser Isolation in a nearby Cloudflare data center (globally within 50 milliseconds of 95% of the Internet-connect population). To ensure website compatibility and security, the target website is entirely executed in a sandboxed Chromium-based browser. Finally, the website is instantly streamed back to the user as vector instructions consumed by a lightweight HTML5-compatible remoting client in the user’s preferred web browser. These safety precautions happen with no perceivable latency to the end user.

Cloudflare Browser Isolation is an extremely secure remote browsing experience that feels just like local browsing. And delivering this is only possible by serving isolated browsers on a low latency, global network with our unique vector based streaming technology. This architecture is different from legacy remote browser isolation solutions that rely on fragile and insecure DOM-scrubbing, or are bandwidth intensive and high latency pixel pushing techniques hosted in a few high latency data centers.

4. Reassess (always learning)

Last but not least, another ingredient that makes Email Link Isolation particularly effective is that behind the scenes our services are constantly reevaluating domains and updating their reputation in Cloudflare’s systems.

When a domain on our suspicious list is confirmed to be benign, all links to it can automatically start opening with the user’s local browser instead of with Cloudflare Browser Isolation.

Similarly, if a domain on the suspicious list is identified as malign, all links to that domain can be immediately blocked from opening. So, our services are constantly learning and acting accordingly.

It’s been four weeks since we deployed Email Link Isolation to all our 3,000+ Cloudflare employees, here’s what we saw:

  • 100,000 link rewrites per week on Spam and Malicious emails. Such emails were already blocked server side by Area 1 and users never see them. It’s still safer to rewrite these as they may be released from quarantine on user request.
  • 2,500 link rewrites per week on Bulk emails. Mostly graymail, which are commercial/bulk communications the user opted into. They may end up in the users’ spam folder.
  • 1,000 link rewrites per week on emails that do not fit any of the categories above — these are the ones that normally reach the user’s inboxes. These are almost certainly benign, but there’s still enough doubt to warrant a link rewrite.
  • 25 clicks on rewritten links per week (up to six per day).
Click Here! (safely): Automagical Browser Isolation for potentially unsafe links in email

As a testament to the efficacy of Cloudflare Area 1, 25 suspicious link clicks per week for a universe of over 3,000 employees is a very low number. Thanks to Email Link Isolation, users were protected against exploits.

Better together with Cloudflare Zero Trust

In future iterations, administrators will be able to connect Cloudflare Area 1 to their Cloudflare Zero Trust account and apply isolation policies, DLP (Data Loss Protection) controls and in-line CASB (a cloud access security broker) to email link isolated traffic.

We are starting our beta today. If you’re interested in trying Email Link Isolation and start to feel safer with your email experience, you should sign up here.

Connect to private network services with Browser Isolation

Post Syndicated from Tim Obezuk original https://blog.cloudflare.com/browser-isolation-private-network/

Connect to private network services with Browser Isolation

Connect to private network services with Browser Isolation

If you’re working in an IT organization that has relied on virtual desktops but looking to get rid of them, we have some good news: starting today, you can connect your users to your private network via isolated remote browsers. This means you can deliver sensitive internal web applications — reducing costs without sacrificing security.

Browser Isolation with private network connectivity enables your users to securely access private web services without installing any software or agents on an endpoint device or absorbing the management and cost overhead of serving virtual desktops. What’s even better: Browser Isolation is natively integrated into Cloudflare’s Zero Trust platform, making it easy to control and monitor who can access what private services from a remote browser without sacrificing performance or security.

Deprecating virtual desktops for web apps

The presence of virtual desktops in the workplace tells an interesting story about the evolution of deploying and securing enterprise applications. Serving a full virtual desktop to end-users is an expensive decision, each user requiring a dedicated virtual machine with multiple CPU cores and gigabytes of memory to run a full operating system. This cost was offset by the benefits of streamlining desktop app distribution and the security benefits of isolating unmanaged devices from the aging application.

Then the launch of Chromium/V8 surprised everyone by demonstrating that desktop-grade applications could be built entirely in web-based technologies.  Today, a vast majority of applications — either SaaS or private — exist within a web browser. With most Virtual Desktop Infrastructure (VDI) users connecting to a remote desktop just to open a web browser, VDI’s utility for distributing applications is really no longer needed and has become a tremendously expensive way to securely host a web browser.

Browser Isolation with private network connectivity enables businesses to maintain the security benefits of VDI, without the costs of hosting and operating legacy virtual desktops.

Transparent end-user experience

But it doesn’t just have a better ROI. Browser Isolation also offers a better experience for your end-users, too. Serving web applications via virtual desktops is a clunky experience. Users first need to connect to their virtual desktop (either through a desktop application or web portal), open an embedded web browser. This model requires users to context-switch between local and remote web applications which adds friction, impacting user productivity.

With Browser Isolation users simply navigate to the isolated private application in their preferred web browser and use the service as if they were directly browsing the remote web browser.

How it works

Browser Isolation with private network connectivity works by unifying our Zero Trust products: Cloudflare Access and Cloudflare Tunnels.

Cloudflare Access authorizes your users via your preferred Identity Provider and connects them to a remote browser without installing any software on their device. Cloudflare Tunnels securely connects your private network to remote browsers hosted on Cloudflare’s network without opening any inbound ports on your firewall.

Monitor third-party users on private networks

Ever needed to give a contractor or vendor access to your network to remotely manage a web UI? Simply add the user to your Clientless Web Isolation policy, and they can connect to your internal service without installing any client software on their device. All requests to private IPs are filtered, inspected, and logged through Cloudflare Gateway.

Apply data protection controls

All traffic from remote browsers into your network is inspected and filtered. Data protection controls such as disabling clipboard, printing and file upload/downloads can be granularly applied to high-risk user groups and sensitive applications.

Get started

Connect your network to Cloudflare Zero Trust

It’s ridiculously easy to connect any network with outbound Internet access.

Engineers needing a web environment to debug and test services inside a private network just need to run a single command to connect their network to Browser Isolation using Cloudflare Tunnels.

Enable Clientless Web Isolation

Clientless Web Isolation allows users to connect to a remote browser without installing any software on the endpoint device. That means company-wide deployment is seamless and transparent to end users. Follow these steps to enable Clientless Web Isolation and define what users are allowed to connect to a remote browser.

Browse private IP resources

Now that you have your network connected to Cloudflare, and your users connected to remote browsers it’s easy for a user to connect to any RFC 1918 address in a remote browser. Simply navigate to your isolation endpoint, and you’ll be connected to your private network.

For example, if you want a user to manage a router hosted at http://192.0.2.1, prefix this URL with your isolation endpoint such as

https://<authdomain>.cloudflareaccess.com/browser/http://192.0.2.1

That’s it! Users are automatically served a remote browser in a nearby Cloudflare data center.

Remote browser connected to a private web service with data loss prevention policies enabled

Define policies

At this point, your users can connect to any private resource inside your network. You may want to further control what endpoints your users can reach. To do this, navigate to Gateway → Policies → HTTP and allow / block or apply data protection controls for any private resource based on identity or destination IP address. See our developer documentation for more information.

Connect to private network services with Browser Isolation

Additionally, isolation policies can be defined to control how users can interact with the remote browser to disable the clipboard, printing or file upload / downloads. See our developer documentation for more information.

Logging and visibility

Finally, all remote browser traffic is logged by the Secure Web Gateway. Navigate to Logs → Gateway → HTTP and filter by identity or destination IP address.

Connect to private network services with Browser Isolation

What’s next?

We’re excited to learn how people use Browser Isolation to enable remote access to private networks and protect sensitive apps. Like always, we’re just getting started so stay tuned for improvements on configuring remote browsers and deeper connectivity with Access applications. Click here to get started with Browser Isolation.

CVE-2022-1096: How Cloudflare Zero Trust provides protection from zero day browser vulnerabilities

Post Syndicated from Tim Obezuk original https://blog.cloudflare.com/cve-2022-1096-zero-trust-protection-from-zero-day-browser-vulnerabilities/

CVE-2022-1096: How Cloudflare Zero Trust provides protection from zero day browser vulnerabilities

CVE-2022-1096: How Cloudflare Zero Trust provides protection from zero day browser vulnerabilities

On Friday, March 25, 2022, Google published an emergency security update for all Chromium-based web browsers to patch a high severity vulnerability (CVE-2022-1096). At the time of writing, the specifics of the vulnerability are restricted until the majority of users have patched their local browsers.

It is important everyone takes a moment to update their local web browser. It’s one quick and easy action everyone can contribute to the cybersecurity posture of their team.

Even if everyone updated their browser straight away, this remains a reactive measure to a threat that existed before the update was available. Let’s explore how Cloudflare takes a proactive approach by mitigating the impact of zero day browser threats with our zero trust and remote browser isolation services. Cloudflare’s remote browser isolation service is built from the ground up to protect against zero day threats, and all remote browsers on our global network have already been patched.

How Cloudflare Zero Trust protects against browser zero day threats

Cloudflare Zero Trust applies a layered defense strategy to protect users from zero day threats while browsing the Internet:

  1. Cloudflare’s roaming client steers Internet traffic over an encrypted tunnel to a nearby Cloudflare data center for inspection and filtration.
  2. Cloudflare’s secure web gateway inspects and filters traffic based on our network intelligence, antivirus scanning and threat feeds. Requests to known malicious services are blocked and high risk or unknown traffic is automatically served by a remote browser.
  3. Cloudflare’s browser isolation service executes all website code in a remote browser to protect unpatched devices from threats inside the unknown website.
CVE-2022-1096: How Cloudflare Zero Trust provides protection from zero day browser vulnerabilities

Protection from the unknown

Zero day threats are often exploited and exist undetected in the real world and actively target users through risky links in emails or other external communication points such as customer support tickets. This risk cannot be eliminated, but it can be reduced by using remote browser isolation to minimize the attack surface. Cloudflare’s browser isolation service is built from the ground up to protect against zero day threats:

  • Prevent compromised web pages from affecting the endpoint device by executing all web code in a remote browser that is physically isolated from the endpoint device. The endpoint device only receives a thin HTML5 remoting shell from our network and vector draw commands from the remote browser.
  • Mitigate the impact of compromise by automatically destroying and reconstructing remote browsers back to a known clean state at the end of their browser session.
  • Protect adjacent remote browsers by encrypting all remote browser egress traffic, segmenting remote browsers with virtualization technologies and distributing browsers across physical hardware in our global network.
  • Aiding Security Incident Response (SIRT) teams by logging all remote egress traffic in the integrated secure web gateway logs.

Patching remote browsers around the world

Even with all these security controls in place, patching browsers remains critical to eliminate the risk of compromise. The process of patching local and remote browsers tells two different stories that can be the difference between compromise, and avoiding a zero day vulnerability.

Patching your workforces local browsers requires politely asking users to interrupt their work to update their browser, or apply mobile device management techniques to disrupt their work by forcing an update. Neither of these options create happy users, or deliver rapid mitigation.

Patching remote browsers is a fundamentally different process. Since the remote browser itself is running on our network, Users and Administrators do not need to intervene as security patches are automatically deployed to remote browsers on Cloudflare’s network. Then without a user restarting their local browser, any traffic to an isolated website is automatically served from a patched remote browser.

Finally, browser based vulnerabilities such as CVE-2022-1096 are not uncommon. With over 300 in 2021 and over 40 already in 2022 (according to cvedetails.com) it is critical for administrators to have a plan to rapidly mitigate and patch browsers in their organization.

Get started with Cloudflare Browser Isolation

Cloudflare Browser Isolation is available to both self serve and enterprise customers. Whether you’re a small startup or a massive enterprise, our network is ready to serve fast and secure remote browsing for your team, no matter where they are based.

To get started, visit our website and, if you’re interested in evaluating Browser Isolation, ask our team for a demo with our Clientless Web Isolation.

Introducing Cloudflare Browser Isolation beta

Post Syndicated from Tim Obezuk original https://blog.cloudflare.com/browser-beta/

Introducing Cloudflare Browser Isolation beta

Reimagining the Browser

Introducing Cloudflare Browser Isolation beta

Web browsers are the culprit behind 70% of endpoint compromises. The same application that connects users to the entire Internet also connects you to all of the potentially harmful parts of the Internet. It’s an open door to nearly every connected system on the planet, which is powerful and terrifying.

We also rely on browsers more than ever. Most applications that we use live in a browser and that will continue to increase. For more and more organizations, a corporate laptop is just a managed web browser machine.

To keep those devices safe, and the data they hold or access, enterprises have started to deploy “browser isolation” services where the browser itself doesn’t run on the machine. Instead, the browser runs on a virtual machine in a cloud provider somewhere. By running away from the device, threats from the browser stay on that virtual machine somewhere in the cloud.

However, most isolation solutions take one of two approaches that both ruin the convenience and flexibility of a web browser:

  • Record the isolated browser and send a live stream of it to the user, which is slow and makes it difficult to do basic things like input text to a form.
  • Unpack the webpage, inspect it, repack it and send it to the user – sometimes missing threats or more often failing to repack the webpage in a way that it still works.

Today, we’re excited to open up a beta of a third approach to keeping web browsing safe with Cloudflare Browser Isolation. Browser sessions run in sandboxed environments in Cloudflare data centers in 200 cities around the world, bringing the remote browser milliseconds away from the user so it feels like local web browsing.

Instead of streaming pixels to the user, Cloudflare Browser Isolation sends the final output of a browser’s web page rendering. The approach means that the only thing ever sent to the device is a package of draw commands to render the webpage, which also makes Cloudflare Browser Isolation compatible with any HTML5 compliant browser.

The result is a browser that just feels like a browser, while keeping threats far away from the device.

We’re inviting users to sign up for the beta today as part of Zero Trust week at Cloudflare. If you’re interested in signing up now, visit the bottom of this post. If you’d like to find out how this works, keep reading.

The unexpected universal productivity application

While it never quite became the replacement operating system Marc Andreessen predicted in 1995, the web browser is perhaps the most important application today on end-user devices. In the workplace, many people spend the majority of their at-work computer time entirely within a web browser connected to internal apps and external SaaS applications and services. As this has occurred, browsers have needed to become increasingly complex — to address the expanding richness of the web and the demands of modern web applications such as Office 365 and Google Workplace.

However, despite the pivotal and ubiquitous role of web browsers, they are the least controlled application in the enterprise. Businesses struggle to control how users interact with web browsers. It’s all too easy for a user to inadvertently download an infected file, install a malicious extension, upload sensitive company data or click a malicious zero-day link in an email or on a webpage.

Making the problem worse is the growing prevalence of BYOD. It makes it difficult to enforce which browsers are used or if they are properly patched. Mobile device management (MDM) is a step in the right direction, but just like the slow patching cycles of on-premise firewalls, MDM can often be too slow to protect against zero day threats. I’ve been the recipient of many mass emails from CISO’s reminding everyone to patch their browser and to do it right now because this time it’s “really important” (CVE-2019-5786).

Reimagining the browser

Earlier this week we announced Cloudflare One, which is our vision for the future of the corporate network. The fundamental approach we’ve taken is a blank sheet: to zero out all the assumptions of the old model (like castle-and-moat) and usher in a new model based on the complex nature of today’s corporate networking and the shift to Zero Trust, cloud-based networking-as-a-service.

It would be impossible to do this without thinking about the browser. Remote computing technologies have offered the promise of fixing the problems of the browser for some time — a future where anyone can benefit from the security and scale of cloud computing on their personal device. The reality has been that getting a generally performant solution is much more difficult than it sounds. It requires sending a user’s input over the Internet, computing that input, retrieving resources off the web, and then streaming them back to the user. And it all must occur in milliseconds, to create an illusion of using a local piece of software.

The general experience has been terrible, and many implementations have created nothing but angry emails and help-desk tickets for IT folks.

It is a tough problem, and it’s something we’ve been hard at work at solving. By delivering a vector-based stream that scales across any display size without requiring high bandwidth connections we’re able to reproduce the native browser experience remotely. Users experience the website as it was intended, without all the compatibility issues introduced by scrubbing HTML, CSS and JavaScript. And performance issues are aided tremendously by the fact that the managed browser is hosted only milliseconds away on our network.

How secure remote browsing fits in with Cloudflare for Teams

Before Cloudflare Browser Isolation, Cloudflare for Teams consisted of two core services:

Cloudflare Access creates a Zero Trust network perimeter that allows users to access corporate applications without needing to poke holes in their internal network with a legacy VPN appliance.

Cloudflare Gateway creates a Secure Web Gateway that protects users from threats on any website.

These tools are excellent for protecting private Internet properties from unauthorized access and web browsing activity from known malicious websites. But what about unknown and unforeseeable threats?

Cloudflare Browser Isolation answers this question by sandboxing a web browser in a remote container that is easily disposed of at the end of the user’s browsing session or when compromised.

Should an unknown threat such as a zero day vulnerability or malicious website exploit any of the hundreds of Web APIs, the attack is limited to a browser running in a supervised cloud environment leaving the end-user’s device unaffected.

The Network is the Computer®

Web browsers are the foundation that the shift to the cloud has been built on. It’s just that they’ve always run in the wrong place.

In the same way that it made no sense for a developer to run and maintain the hardware that their application runs on, the same exact case can be made for the other side of the cloud’s equation: the browser. Funnily enough, the solution is exactly the same: like the developer’s application, the browser needed to move to the cloud. However, as with all disruptions, it takes time and investment for the performance of the new technology to catch up to the old one. When AWS was first launched in 2006, the inherent limitations meant that for most developers, it made sense to continue to run on-premise solutions.

At some point though, the technology improves to the point where the disruption can start taking over from the previous paradigm.

The limiting factor until today for a cloud-based browser has often been the experience of using it. A user’s experience is limited by the speed of light; it limits the time it takes a user’s input to travel to the remote data center and be returned to their display. In a perfect world, this needs to occur within milliseconds to deliver a real time experience.

Cloudflare has one very big advantage in solving that problem.

Introducing Cloudflare Browser Isolation beta

To deliver real-time remote computing experiences, each of our 200+ data centers are capable of serving remote browsing sessions within the blink of an eye of nearly everyone connected to the Internet. This allows us to deliver a low latency, responsive stream of a webpage regardless of where you’re physically located.

What’s next?

But that’s enough talking about it. We’d love for you to try it! Please complete the form here to sign up to be one of the first users of this new technology in our network. We’ll be in touch as we expand the beta to more users.