Tag Archives: vulnerabilities

Missouri Governor Doesn’t Understand Responsible Disclosure

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2021/10/the-missouri-governor-doesnt-understand-responsible-disclosure.html

The Missouri governor wants to prosecute the reporter who discovered a security vulnerability in a state’s website, and then reported it to the state.

The newspaper agreed to hold off publishing any story while the department fixed the problem and protected the private information of teachers around the state.

[…]

According to the Post-Dispatch, one of its reporters discovered the flaw in a web application allowing the public to search teacher certifications and credentials. No private information was publicly visible, but teacher Social Security numbers were contained in HTML source code of the pages.

The state removed the search tool after being notified of the issue by the Post-Dispatch. It was unclear how long the Social Security numbers had been vulnerable.

[…]

Chris Vickery, a California-based data security expert, told The Independent that it appears the department of education was “publishing data that it shouldn’t have been publishing.

“That’s not a crime for the journalists discovering it,” he said. “Putting Social Security numbers within HTML, even if it’s ‘non-display rendering’ HTML, is a stupid thing for the Missouri website to do and is a type of boneheaded mistake that has been around since day one of the Internet. No exploit, hacking or vulnerability is involved here.”

In explaining how he hopes the reporter and news organization will be prosecuted, [Gov.] Parson pointed to a state statute defining the crime of tampering with computer data. Vickery said that statute wouldn’t work in this instance because of a recent decision by the U.S. Supreme Court in the case of Van Buren v. United States.

One hopes that someone will calm the governor down.

Brian Krebs has more.

Helping Apache Servers stay safe from zero-day path traversal attacks (CVE-2021-41773)

Post Syndicated from Michael Tremante original https://blog.cloudflare.com/helping-apache-servers-stay-safe-from-zero-day-path-traversal-attacks/

Helping Apache Servers stay safe from zero-day path traversal attacks (CVE-2021-41773)

Helping Apache Servers stay safe from zero-day path traversal attacks (CVE-2021-41773)

On September 29, 2021, the Apache Security team was alerted to a path traversal vulnerability being actively exploited (zero-day) against Apache HTTP Server version 2.4.49. The vulnerability, in some instances, can allow an attacker to fully compromise the web server via remote code execution (RCE) or at the very least access sensitive files. CVE number 2021-41773 has been assigned to this issue. Both Linux and Windows based servers are vulnerable.

An initial patch was made available on October 4 with an update to 2.4.50, however, this was found to be insufficient resulting in an additional patch bumping the version number to 2.4.51 on October 7th (CVE-2021-42013).

Customers using Apache HTTP Server versions 2.4.49 and 2.4.50 should immediately update to version 2.4.51 to mitigate the vulnerability. Details on how to update can be found on the official Apache HTTP Server project site.

Any Cloudflare customer with the setting normalize URLs to origin turned on have always been protected against this vulnerability.

Additionally, customers who have access to the Cloudflare Web Application Firewall (WAF), receive additional protection by turning on the rule with the following IDs:

  • 1c3d3022129c48e9bb52e953fe8ceb2f (for our new WAF)
  • 100045A (for our legacy WAF)

The rule can also be identified by the following description:

Rule message: Anomaly:URL:Query String - Multiple Slashes, Relative Paths, CR, LF or NULL.

Given the nature of the vulnerability, attackers would normally try to access sensitive files (for example /etc/passwd), and as such, many other Cloudflare Managed Rule signatures are also effective at stopping exploit attempts depending on the file being accessed.

How the vulnerability works

The vulnerability leverages missing path normalization logic. If the Apache server is not configured with a require all denied directive for files outside the document root, attackers can craft special URLs to read any file on the file system accessible by the Apache process. Additionally, this flaw could also leak the source of interpreted files like CGI scripts and, in some cases, also allow the attacker to take over the web server by executing shell scripts.

For example, the following path:

$hostname/cgi-bin/../../../etc/passwd

would allow the attacker to climb the directory tree (../ indicates parent directory) outside of the web server document root and then subsequently access /etc/passwd.

Well implemented path normalization logic would correctly collapse the path into the shorter $hostname/etc/passwd by normalizing all ../ character sequences nullifying the attempt to climb up the directory tree.

Correct normalization is not easy as it also needs to take into consideration character encoding, such as percent encoded characters used in URLs. For example, the following path is equivalent to the first one provided:

$hostname/cgi-bin/.%2e/%2e%2e/%2e%2e/etc/passwd

as the characters %2e represent the percent encoded version of dot “.”. Not taking this properly into account was the cause of the vulnerability.

The PoC for this vulnerability is straightforward and simply relies on attempting to access sensitive files on vulnerable Apache web servers.

Exploit Attempts

Cloudflare has seen a sharp increase in attempts to exploit and find vulnerable servers since October 5.

Helping Apache Servers stay safe from zero-day path traversal attacks (CVE-2021-41773)

Most exploit attempts observed have been probing for static file paths — indicating heavy scanning activity before attackers (or researchers) may have attempted more sophisticated techniques that could lead to remote code execution. The most commonly attempted file paths are reported below:

/cgi-bin/.%2e/.git/config
/cgi-bin/.%2e/app/etc/local.xml
/cgi-bin/.%2e/app/etc/env.php
/cgi-bin/.%2e/%2e%2e/%2e%2e/etc/passwd

Conclusion

Keeping web environments safe is not an easy task. Attackers will normally gain access and try to exploit vulnerabilities even before PoCs become widely available — we reported such a case not too long ago with Atlassian’s Confluence OGNL vulnerability.

It is vital to employ all security measures available. Cloudflare features such as our URL normalization and the WAF, are easy to implement and can buy time to deploy any relevant patches offered by the affected software vendors.

How Cloudflare helped mitigate the Atlassian Confluence OGNL vulnerability before the PoC was released

Post Syndicated from Michael Tremante original https://blog.cloudflare.com/how-cloudflare-helped-mitigate-the-atlassian-confluence-ognl-vulnerability-before-the-poc-was-released/

How Cloudflare helped mitigate the Atlassian Confluence OGNL vulnerability before the PoC was released

How Cloudflare helped mitigate the Atlassian Confluence OGNL vulnerability before the PoC was released

On August 25, 2021, Atlassian released a security advisory for their Confluence Server and Data Center. The advisory highlighted an Object-Graph Navigation Language (OGNL) injection that would result in an unauthenticated attacker being able to execute arbitrary code.

A full proof of concept (PoC) of the attack was made available by a security researcher on August 31, 2021. Cloudflare immediately reviewed the PoC and prepared a mitigation rule via an emergency release. The rule, once tested, was deployed on September 1, 2021, at 15:32 UTC with a default action of BLOCK and the following IDs:

  • 100400 (for our legacy WAF)
  • e8c550810618437c953cf3a969e0b97a (for our new WAF)

All customers using the Cloudflare WAF to protect their self-hosted Confluence applications have automatically been protected since the new rule was deployed last week. Additionally, the Cloudflare WAF started blocking a high number of potentially malicious requests to Confluence applications even before the rule was deployed.

And customers who had deployed Cloudflare Access in front of their Confluence applications were already protected even before the emergency release. Access checks every request made to a protected hostname for a JSON Web Token (JWT) containing a user’s identity. Any unauthenticated users attempting this exploit would have been blocked before they could reach the Confluence server.

Customers must, however, immediately update their self-hosted Confluence installations to the versions listed in the advisory to ensure full protection.

This vulnerability was assigned the CVE number 2021-26084 and has a base score of 9.8 — critical. A detailed technical write-up of the vulnerability along with the PoC can be found on GitHub.

Timeline of Events

A timeline of events is provided below:

2021-08-25 at 17:00 UTC Atlassian security advisory released
2021-08-28 Cloudflare WAF starts seeing and blocking malicious traffic targeting vulnerable endpoints related to the security advisory
2021-08-31 at 22:22 UTC A PoC becomes widely available
2021-09-01 at 15:32 UTC Additional Cloudflare WAF rule to target CVE-2021-26084

How soon were attackers probing vulnerable endpoints?

High profile vulnerabilities tend to be exploited very quickly by attackers once a PoC or a patch becomes available. Cloudflare maintains aggregated and sampled data on WAF blocks1 that can be used to explore how quickly vulnerable endpoints start receiving malicious traffic, highlighting the importance of deploying patches as quickly as possible.

Cloudflare data suggests that scanning for the vulnerability started up to three days before the first publicly available PoC was published, as high WAF activity was observed on vulnerable endpoints beginning August 28, 2021. This activity may indicate that attackers or researchers had successfully reverse engineered the patch within that time frame.

It also shows that, even without the specific WAF rule that we rolled out for this vulnerability, Cloudflare was blocking attempts to exploit it. Other WAF rules picked up the suspect behavior.

For this vulnerability, two endpoints are highlighted that can be used to explore attack traffic:

  • /pages/doenterpagevariables.action
  • /pages/createpage-entervariables.action

The following graph shows traffic matching Cloudflare’s WAF security feature from August 21 to September 5, 2021. Specifically:

  • In blue: HTTP requests blocked by Cloudflare’s WAF matching the two chosen paths.
  • In red: HTTP requests blocked by Cloudflare’s WAF matching the two paths and the specific rule deployed to cover this vulnerability.
How Cloudflare helped mitigate the Atlassian Confluence OGNL vulnerability before the PoC was released

By looking at the data, an increase in activity can be seen starting from August 28, 2021 — far beyond normal Internet background noise levels. Additionally, more than 64% of the traffic increase was detected and blocked by the Cloudflare WAF as malicious on the day the PoC was available.

What were attackers trying before a PoC was widely available?

Just before a PoC became widely available, an increasing number of requests were blocked by customer configured IP based rules, followed by our Managed Rulesets and rate limiting. Most custom WAF rules and IP based rules are created by customers either in response to malicious activity in the WAF logs, or as a positive security model to lock down applications that should simply not have public access from the Internet.

We can zoom into the Managed WAF rule matches to explore what caused the WAF to trigger before the specific rule was deployed:

How Cloudflare helped mitigate the Atlassian Confluence OGNL vulnerability before the PoC was released

Command injection based attacks were the most common vector attempted before a PoC was made widely available, indicating again that some attackers may have been at least partially aware of the nature of the vulnerability. These attacks are aimed at executing remote code on the target application servers and are often platform specific. Other attack types observed, in order of frequency were:

  • Request Port Anomalies: these are HTTP requests to uncommon ports that are normally not exposed for HTTP traffic.
  • Fake Bot Signatures: these requests matched many of our rules aimed at detecting user agents spoofing themselves as popular bots such as Google, Yandex, Bing and others.
  • OWASP Inbound Anomaly Score Exceeded: these are requests that were flagged by our implementation of the OWASP ModSecurity Core Ruleset. The OWASP ruleset is a score based system that scans requests for patterns of characters that normally identify malicious requests;
  • HTTP Request Anomalies: these requests triggered many of our HTTP based validation checks including but not limited to RFC compliance checks.

Conclusions

Patching zero-day attacks as quickly as possible is vital for security. No single approach can be 100% successful at mitigating intrusion attempts. By observing patterns and triggers for this specific CVE, it is clear that a layered approach is most effective for protecting critical infrastructure. Cloudflare data also implies that, at least in part, some attackers or researchers were aware of the nature of the vulnerability at least since August 28, 2021, three days before a PoC was made widely available.

1The WAF block data consists of sampled matches of request fields including path, geography, rule ID, timestamp and other similar metadata.

Tracking People by their MAC Addresses

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2021/09/tracking-people-by-their-mac-addresses.html

Yet another article on the privacy risks of static MAC addresses and always-on Bluetooth connections. This one is about wireless headphones.

The good news is that product vendors are fixing this:

Several of the headphones which could be tracked over time are for sale in electronics stores, but according to two of the manufacturers NRK have spoken to, these models are being phased out.

“The products in your line-up, Elite Active 65t, Elite 65e and Evolve 75e, will be going out of production before long and newer versions have already been launched with randomized MAC addresses. We have a lot of focus on privacy by design and we continuously work with the available security measures on the market,” head of PR at Jabra, Claus Fonnesbech says.

“To run Bluetooth Classic we, and all other vendors, are required to have static addresses and you will find that in older products,” Fonnesbech says.

Jens Bjørnkjær Gamborg, head of communications at Bang & Olufsen, says that “this is products that were launched several years ago.”

“All products launched after 2019 randomize their MAC-addresses on a frequent basis as it has become the market standard to do so,” Gamborg says.

EDITED TO ADD (9/13): It’s not enough to randomly change MAC addresses. Any other plaintext identifiers need to be changed at the same time.

Interesting Privilege Escalation Vulnerability

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2021/08/interesting-privilege-escalation-vulnerability.html

If you plug a Razer peripheral (mouse or keyboard, I think) into a Windows 10 or 11 machine, you can use a vulnerability in the Razer Synapse software — which automatically downloads — to gain SYSTEM privileges.

It should be noted that this is a local privilege escalation (LPE) vulnerability, which means that you need to have a Razer devices and physical access to a computer. With that said, the bug is so easy to exploit as you just need to spend $20 on Amazon for Razer mouse and plug it into Windows 10 to become an admin.

Cobalt Strike Vulnerability Affects Botnet Servers

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2021/08/cobolt-strike-vulnerability-affects-botnet-servers.html

Cobalt Strike is a security tool, used by penetration testers to simulate network attackers. But it’s also used by attackers — from criminals to governments — to automate their own attacks. Researchers have found a vulnerability in the product.

The main components of the security tool are the Cobalt Strike client — also known as a Beacon — and the Cobalt Strike team server, which sends commands to infected computers and receives the data they exfiltrate. An attacker starts by spinning up a machine running Team Server that has been configured to use specific “malleability” customizations, such as how often the client is to report to the server or specific data to periodically send.

Then the attacker installs the client on a targeted machine after exploiting a vulnerability, tricking the user or gaining access by other means. From then on, the client will use those customizations to maintain persistent contact with the machine running the Team Server.

The link connecting the client to the server is called the web server thread, which handles communication between the two machines. Chief among the communications are “tasks” servers send to instruct clients to run a command, get a process list, or do other things. The client then responds with a “reply.”

Researchers at security firm SentinelOne recently found a critical bug in the Team Server that makes it easy to knock the server offline. The bug works by sending a server fake replies that “squeeze every bit of available memory from the C2’s web server thread….”

It’s a pretty serious vulnerability, and there’s already a patch available. But — and this is the interesting part — that patch is available to licensed users, which attackers often aren’t. It’ll be a while before that patch filters down to the pirated copies of the software, and that time window gives defenders an opportunity. They can simulate a Cobolt Strike client, and leverage this vulnerability to reply to servers with messages that cause the server to crash.

Nasty Windows Printer Driver Vulnerability

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2021/07/nasty-printer-driver-vulnerability.html

From SentinelLabs, a critical vulnerability in HP printer drivers:

Researchers have released technical details on a high-severity privilege-escalation flaw in HP printer drivers (also used by Samsung and Xerox), which impacts hundreds of millions of Windows machines.

If exploited, cyberattackers could bypass security products; install programs; view, change, encrypt or delete data; or create new accounts with more extensive user rights.

The bug (CVE-2021-3438) has lurked in systems for 16 years, researchers at SentinelOne said, but was only uncovered this year. It carries an 8.8 out of 10 rating on the CVSS scale, making it high-severity.

Look for your printer here, and download the patch if there is one.

China Taking Control of Zero-Day Exploits

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2021/07/china-taking-control-of-zero-day-exploits.html

China is making sure that all newly discovered zero-day exploits are disclosed to the government.

Under the new rules, anyone in China who finds a vulnerability must tell the government, which will decide what repairs to make. No information can be given to “overseas organizations or individuals” other than the product’s manufacturer.

No one may “collect, sell or publish information on network product security vulnerabilities,” say the rules issued by the Cyberspace Administration of China and the police and industry ministries.

This just blocks the cyber-arms trade. It doesn’t prevent researchers from telling the products’ companies, even if they are outside of China.

Details of the REvil Ransomware Attack

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2021/07/details-of-the-revil-ransomware-attack.html

ArsTechnica has a good story on the REvil ransomware attack of last weekend, with technical details:

This weekend’s attack was carried out with almost surgical precision. According to Cybereason, the REvil affiliates first gained access to targeted environments and then used the zero-day in the Kaseya Agent Monitor to gain administrative control over the target’s network. After writing a base-64-encoded payload to a file named agent.crt the dropper executed it.

[…]

The ransomware dropper Agent.exe is signed with a Windows-trusted certificate that uses the registrant name “PB03 TRANSPORT LTD.” By digitally signing their malware, attackers are able to suppress many security warnings that would otherwise appear when it’s being installed. Cybereason said that the certificate appears to have been used exclusively by REvil malware that was deployed during this attack.

To add stealth, the attackers used a technique called DLL Side-Loading, which places a spoofed malicious DLL file in a Windows’ WinSxS directory so that the operating system loads the spoof instead of the legitimate file. In the case here, Agent.exe drops an outdated version that is vulnerable to DLL Side-Loading of “msmpeng.exe,” which is the file for the Windows Defender executable.

Once executed, the malware changes the firewall settings to allow local windows systems to be discovered. Then, it starts to encrypt the files on the system….

REvil is demanding $70 million for a universal decryptor that will recover the data from the 1,500 affected Kaseya customers.

More news.

Note that this is yet another supply-chain attack. Instead of infecting those 1,500 networks directly, REvil infected a single managed service provider. And it leveraged a zero-day vulnerability in that provider.

EDITED TO ADD (7/13): Employees warned Kaseya’s management for years about critical security flaws, but they were ignored.

Vulnerability in the Kaspersky Password Manager

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2021/07/vulnerability-in-the-kaspersky-password-manager.html

A vulnerability (just patched) in the random number generator used in the Kaspersky Password Manager resulted in easily guessable passwords:

The password generator included in Kaspersky Password Manager had several problems. The most critical one is that it used a PRNG not suited for cryptographic purposes. Its single source of entropy was the current time. All the passwords it created could be bruteforced in seconds. This article explains how to securely generate passwords, why Kaspersky Password Manager failed, and how to exploit this flaw. It also provides a proof of concept to test if your version is vulnerable.

The product has been updated and its newest versions aren’t affected by this issue.

Stupid programming mistake, or intentional backdoor? We don’t know.

More generally: generating random numbers is hard. I recommend my own algorithm: Fortuna. I also recommend my own password manager: Password Safe.

EDITED TO ADD: Commentary from Matthew Green.

Risks of Evidentiary Software

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2021/06/risks-of-evidentiary-software.html

Over at Lawfare, Susan Landau has an excellent essay on the risks posed by software used to collect evidence (a Breathalyzer is probably the most obvious example).

Bugs and vulnerabilities can lead to inaccurate evidence, but the proprietary nature of software makes it hard for defendants to examine it.

The software engineers proposed a three-part test. First, the court should have access to the “Known Error Log,” which should be part of any professionally developed software project. Next the court should consider whether the evidence being presented could be materially affected by a software error. Ladkin and his co-authors noted that a chain of emails back and forth are unlikely to have such an error, but the time that a software tool logs when an application was used could easily be incorrect. Finally, the reliability experts recommended seeing whether the code adheres to an industry standard used in an non-computerized version of the task (e.g., bookkeepers always record every transaction, and thus so should bookkeeping software).

[…]

Inanimate objects have long served as evidence in courts of law: the door handle with a fingerprint, the glove found at a murder scene, the Breathalyzer result that shows a blood alcohol level three times the legal limit. But the last of those examples is substantively different from the other two. Data from a Breathalyzer is not the physical entity itself, but rather a software calculation of the level of alcohol in the breath of a potentially drunk driver. As long as the breath sample has been preserved, one can always go back and retest it on a different device.

What happens if the software makes an error and there is no sample to check or if the software itself produces the evidence? At the time of our writing the article on the use of software as evidence, there was no overriding requirement that law enforcement provide a defendant with the code so that they might examine it themselves.

[…]

Given the high rate of bugs in complex software systems, my colleagues and I concluded that when computer programs produce the evidence, courts cannot assume that the evidentiary software is reliable. Instead the prosecution must make the code available for an “adversarial audit” by the defendant’s experts. And to avoid problems in which the government doesn’t have the code, government procurement contracts must include delivery of source code­ — code that is more-or-less readable by people — ­for every version of the code or device.

NFC Flaws in POS Devices and ATMs

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2021/06/nfc-flaws-in-pos-devices-and-atms.html

It’s a series of vulnerabilities:

Josep Rodriguez, a researcher and consultant at security firm IOActive, has spent the last year digging up and reporting vulnerabilities in the so-called near-field communications reader chips used in millions of ATMs and point-of-sale systems worldwide. NFC systems are what let you wave a credit card over a reader — rather than swipe or insert it — to make a payment or extract money from a cash machine. You can find them on countless retail store and restaurant counters, vending machines, taxis, and parking meters around the globe.

Now Rodriguez has built an Android app that allows his smartphone to mimic those credit card radio communications and exploit flaws in the NFC systems’ firmware. With a wave of his phone, he can exploit a variety of bugs to crash point-of-sale devices, hack them to collect and transmit credit card data, invisibly change the value of transactions, and even lock the devices while displaying a ransomware message. Rodriguez says he can even force at least one brand of ATMs to dispense cash­though that “jackpotting” hack only works in combination with additional bugs he says he’s found in the ATMs’ software. He declined to specify or disclose those flaws publicly due to nondisclosure agreements with the ATM vendors.

Protecting against recently disclosed Microsoft Exchange Server vulnerabilities: CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, and CVE-2021-27065

Post Syndicated from Patrick R. Donahue original https://blog.cloudflare.com/protecting-against-microsoft-exchange-server-cves/

Protecting against recently disclosed Microsoft Exchange Server vulnerabilities: CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, and CVE-2021-27065

Enabling the Cloudflare WAF and Cloudflare Specials ruleset protects against exploitation of unpatched CVEs: CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, and CVE-2021-27065.

Cloudflare has deployed managed rules protecting customers against a series of remotely exploitable vulnerabilities that were recently found in Microsoft Exchange Server. Web Application Firewall customers with the Cloudflare Specials ruleset enabled are automatically protected against CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, and CVE-2021-27065.

If you are running Exchange Server 2013, 2016, or 2019, and do not have the Cloudflare Specials ruleset enabled, we strongly recommend that you do so. You should also follow Microsoft’s urgent recommendation to patch your on-premise systems immediately. These vulnerabilities are actively being exploited in the wild by attackers to exfiltrate email inbox content and move laterally within organizations’ IT systems.

Edge Mitigation

If you are running the Cloudflare WAF and have enabled the Cloudflare Specials ruleset, there is nothing else you need to do. We have taken the unusual step of immediately deploying these rules in “Block” mode given active attempted exploitation.

If you wish to disable the rules for any reason, e.g., you are experiencing a false positive mitigation, you can do so by following these instructions:

  1. Login to the Cloudflare Dashboard and click on the Cloudflare Firewall tab and then Managed Rules.
  2. Click on the “Advanced” link at the bottom of the Cloudflare Managed Ruleset card and search for rule ID 100179. Select any appropriate action or disable the rule.
  3. Repeat step #2 for rule ID 100181.

Server Side Mitigation

In addition to blocking attacks at the edge, we recommend that you follow Microsoft’s urgent recommendation to patch your on-premise systems immediately. For those that are unable to immediately patch their systems, Microsoft posted yesterday with interim mitigations that can be applied.

To determine whether your system is (still) exploitable, you can run an Nmap script posted by Microsoft to GitHub: https://github.com/microsoft/CSS-Exchange/blob/main/Security/http-vuln-cve2021-26855.nse.

Vulnerability Details

The attacks observed in the wild take advantage of multiple CVEs that can result in exfiltration of email inboxes and remote code execution when chained together. Security researchers at Volexity have published a detailed analysis of the zero-day vulnerabilities.

Briefly, attackers are:

  1. First exploiting a server-side request forgery (SSRF) vulnerability documented as CVE-2021-26855 to send arbitrary HTTP requests and authenticate as the Microsoft Exchange server.
  2. Using this SYSTEM-level authentication to send SOAP payloads that are insecurely deserialized by the Unified Messaging Service, as documented in CVE-2021-26857. An example of the malicious SOAP payload can be found in the Volexity post linked above.
  3. Additionally taking advantage of CVE-2021-26858 and CVE-2021-27065 to upload arbitrary files such as webshells that allow further exploitation of the system along with a base to move laterally to other systems and networks. These file writes require authentication but this can be bypassed using CVE-2021-26855.

All 4 of the CVEs listed above are blocked by the recently deployed Cloudflare Specials rules: 100179 and 100181. Additionally, existing rule ID 100173, also enabled to Block by default, partially mitigates the vulnerability by blocking the upload of certain scripts.

Additional Recommendations

Organizations can deploy additional protections against this type of attack by adopting a Zero Trust model and making the Exchange server available only to trusted connections. The CVE guidance recommends deploying a VPN or other solutions to block attempts to reach public endpoints. In addition to the edge mitigations from the Cloudflare WAF, your team can protect your Exchange server by using Cloudflare for Teams to block all unauthorized requests.

Twelve-Year-Old Vulnerability Found in Windows Defender

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2021/02/twelve-year-old-vulnerability-found-in-windows-defender.html

Researchers found, and Microsoft has patched, a vulnerability in Windows Defender that has been around for twelve years. There is no evidence that anyone has used the vulnerability during that time.

The flaw, discovered by researchers at the security firm SentinelOne, showed up in a driver that Windows Defender — renamed Microsoft Defender last year — uses to delete the invasive files and infrastructure that malware can create. When the driver removes a malicious file, it replaces it with a new, benign one as a sort of placeholder during remediation. But the researchers discovered that the system doesn’t specifically verify that new file. As a result, an attacker could insert strategic system links that direct the driver to overwrite the wrong file or even run malicious code.

It isn’t unusual that vulnerabilities lie around for this long. They can’t be fixed until someone finds them, and people aren’t always looking.

Dependency Confusion: Another Supply-Chain Vulnerability

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2021/02/dependency-confusion-another-supply-chain-vulnerability.html

Alex Birsan writes about being able to install malware into proprietary corporate software by naming the code files to be identical to internal corporate code files. From a ZDNet article:

Today, developers at small or large companies use package managers to download and import libraries that are then assembled together using build tools to create a final app.

This app can be offered to the company’s customers or can be used internally at the company as an employee tool.

But some of these apps can also contain proprietary or highly-sensitive code, depending on their nature. For these apps, companies will often use private libraries that they store inside a private (internal) package repository, hosted inside the company’s own network.

When apps are built, the company’s developers will mix these private libraries with public libraries downloaded from public package portals like npm, PyPI, NuGet, or others.

[…]

Researchers showed that if an attacker learns the names of private libraries used inside a company’s app-building process, they could register these names on public package repositories and upload public libraries that contain malicious code.

The “dependency confusion” attack takes place when developers build their apps inside enterprise environments, and their package manager prioritizes the (malicious) library hosted on the public repository instead of the internal library with the same name.

The research team said they put this discovery to the test by searching for situations where big tech firms accidentally leaked the names of various internal libraries and then registered those same libraries on package repositories like npm, RubyGems, and PyPI.

Using this method, researchers said they successfully loaded their (non-malicious) code inside apps used by 35 major tech firms, including the likes of Apple, Microsoft, PayPal, Shopify, Netflix, Yelp, Uber, and others.

Clever attack, and one that has netted him $130K in bug bounties.

More news articles.

Router Security

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2021/02/router-security.html

This report is six months old, and I don’t know anything about the organization that produced it, but it has some alarming data about router security.

Conclusion: Our analysis showed that Linux is the most used OS running on more than 90% of the devices. However, many routers are powered by very old versions of Linux. Most devices are still powered with a 2.6 Linux kernel, which is no longer maintained for many years. This leads to a high number of critical and high severity CVEs affecting these devices.

Since Linux is the most used OS, exploit mitigation techniques could be enabled very easily. Anyhow, they are used quite rarely by most vendors except the NX feature.

A published private key provides no security at all. Nonetheless, all but one vendor spread several private keys in almost all firmware images.

Mirai used hard-coded login credentials to infect thousands of embedded devices in the last years. However, hard-coded credentials can be found in many of the devices and some of them are well known or at least easy crackable.

However, we can tell for sure that the vendors prioritize security differently. AVM does better job than the other vendors regarding most aspects. ASUS and Netgear do a better job in some aspects than D-Link, Linksys, TP-Link and Zyxel.

Additionally, our evaluation showed that large scale automated security analysis of embedded devices is possible today utilizing just open source software. To sum it up, our analysis shows that there is no router without flaws and there is no vendor who does a perfect job regarding all security aspects. Much more effort is needed to make home routers as secure as current desktop of server systems.

One comment on the report:

One-third ship with Linux kernel version 2.6.36 was released in October 2010. You can walk into a store today and buy a brand new router powered by software that’s almost 10 years out of date! This outdated version of the Linux kernel has 233 known security vulnerabilities registered in the Common Vulnerability and Exposures (CVE) database. The average router contains 26 critically-rated security vulnerabilities, according to the study.

We know the reasons for this. Most routers are designed offshore, by third parties, and then private labeled and sold by the vendors you’ve heard of. Engineering teams come together, design and build the router, and then disperse. There’s often no one around to write patches, and most of the time router firmware isn’t even patchable. The way to update your home router is to throw it away and buy a new one.

And this paper demonstrates that even the new ones aren’t likely to be secure.

Russia’s SolarWinds Attack

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/12/russias-solarwinds-attack.html

Recent news articles have all been talking about the massive Russian cyberattack against the United States, but that’s wrong on two accounts. It wasn’t a cyberattack in international relations terms, it was espionage. And the victim wasn’t just the US, it was the entire world. But it was massive, and it is dangerous.

Espionage is internationally allowed in peacetime. The problem is that both espionage and cyberattacks require the same computer and network intrusions, and the difference is only a few keystrokes. And since this Russian operation isn’t at all targeted, the entire world is at risk — and not just from Russia. Many countries carry out these sorts of operations, none more extensively than the US. The solution is to prioritize security and defense over espionage and attack.

Here’s what we know: Orion is a network management product from a company named SolarWinds, with over 300,000 customers worldwide. Sometime before March, hackers working for the Russian SVR — previously known as the KGB — hacked into SolarWinds and slipped a backdoor into an Orion software update. (We don’t know how, but last year the company’s update server was protected by the password “solarwinds123” — something that speaks to a lack of security culture.) Users who downloaded and installed that corrupted update between March and June unwittingly gave SVR hackers access to their networks.

This is called a supply-chain attack, because it targets a supplier to an organization rather than an organization itself — and can affect all of a supplier’s customers. It’s an increasingly common way to attack networks. Other examples of this sort of attack include fake apps in the Google Play store, and hacked replacement screens for your smartphone.

SolarWinds has removed its customer list from its website, but the Internet Archive saved it: all five branches of the US military, the state department, the White House, the NSA, 425 of the Fortune 500 companies, all five of the top five accounting firms, and hundreds of universities and colleges. In an SEC filing, SolarWinds said that it believes “fewer than 18,000” of those customers installed this malicious update, another way of saying that more than 17,000 did.

That’s a lot of vulnerable networks, and it’s inconceivable that the SVR penetrated them all. Instead, it chose carefully from its cornucopia of targets. Microsoft’s analysis identified 40 customers who were infiltrated using this vulnerability. The great majority of those were in the US, but networks in Canada, Mexico, Belgium, Spain, the UK, Israel and the UAE were also targeted. This list includes governments, government contractors, IT companies, thinktanks, and NGOs — and it will certainly grow.

Once inside a network, SVR hackers followed a standard playbook: establish persistent access that will remain even if the initial vulnerability is fixed; move laterally around the network by compromising additional systems and accounts; and then exfiltrate data. Not being a SolarWinds customer is no guarantee of security; this SVR operation used other initial infection vectors and techniques as well. These are sophisticated and patient hackers, and we’re only just learning some of the techniques involved here.

Recovering from this attack isn’t easy. Because any SVR hackers would establish persistent access, the only way to ensure that your network isn’t compromised is to burn it to the ground and rebuild it, similar to reinstalling your computer’s operating system to recover from a bad hack. This is how a lot of sysadmins are going to spend their Christmas holiday, and even then they can&;t be sure. There are many ways to establish persistent access that survive rebuilding individual computers and networks. We know, for example, of an NSA exploit that remains on a hard drive even after it is reformatted. Code for that exploit was part of the Equation Group tools that the Shadow Brokers — again believed to be Russia — stole from the NSA and published in 2016. The SVR probably has the same kinds of tools.

Even without that caveat, many network administrators won’t go through the long, painful, and potentially expensive rebuilding process. They’ll just hope for the best.

It’s hard to overstate how bad this is. We are still learning about US government organizations breached: the state department, the treasury department, homeland security, the Los Alamos and Sandia National Laboratories (where nuclear weapons are developed), the National Nuclear Security Administration, the National Institutes of Health, and many more. At this point, there’s no indication that any classified networks were penetrated, although that could change easily. It will take years to learn which networks the SVR has penetrated, and where it still has access. Much of that will probably be classified, which means that we, the public, will never know.

And now that the Orion vulnerability is public, other governments and cybercriminals will use it to penetrate vulnerable networks. I can guarantee you that the NSA is using the SVR’s hack to infiltrate other networks; why would they not? (Do any Russian organizations use Orion? Probably.)

While this is a security failure of enormous proportions, it is not, as Senator Richard Durban said, “virtually a declaration of war by Russia on the United States.” While President-elect Biden said he will make this a top priority, it’s unlikely that he will do much to retaliate.

The reason is that, by international norms, Russia did nothing wrong. This is the normal state of affairs. Countries spy on each other all the time. There are no rules or even norms, and it’s basically “buyer beware.” The US regularly fails to retaliate against espionage operations — such as China’s hack of the Office of Personal Management (OPM) and previous Russian hacks — because we do it, too. Speaking of the OPM hack, the then director of national intelligence, James Clapper, said: “You have to kind of salute the Chinese for what they did. If we had the opportunity to do that, I don’t think we’d hesitate for a minute.”

We don’t, and I’m sure NSA employees are grudgingly impressed with the SVR. The US has by far the most extensive and aggressive intelligence operation in the world. The NSA’s budget is the largest of any intelligence agency. It aggressively leverages the US’s position controlling most of the internet backbone and most of the major internet companies. Edward Snowden disclosed many targets of its efforts around 2014, which then included 193 countries, the World Bank, the IMF and the International Atomic Energy Agency. We are undoubtedly running an offensive operation on the scale of this SVR operation right now, and it’ll probably never be made public. In 2016, President Obama boasted that we have “more capacity than anybody both offensively and defensively.”

He may have been too optimistic about our defensive capability. The US prioritizes and spends many times more on offense than on defensive cybersecurity. In recent years, the NSA has adopted a strategy of “persistent engagement,” sometimes called “defending forward.” The idea is that instead of passively waiting for the enemy to attack our networks and infrastructure, we go on the offensive and disrupt attacks before they get to us. This strategy was credited with foiling a plot by the Russian Internet Research Agency to disrupt the 2018 elections.

But if persistent engagement is so effective, how could it have missed this massive SVR operation? It seems that pretty much the entire US government was unknowingly sending information back to Moscow. If we had been watching everything the Russians were doing, we would have seen some evidence of this. The Russians’ success under the watchful eye of the NSA and US Cyber Command shows that this is a failed approach.

And how did US defensive capability miss this? The only reason we know about this breach is because, earlier this month, the security company FireEye discovered that it had been hacked. During its own audit of its network, it uncovered the Orion vulnerability and alerted the US government. Why don’t organizations like the Departments of State, Treasury and Homeland Wecurity regularly conduct that level of audit on their own systems? The government’s intrusion detection system, Einstein 3, failed here because it doesn’t detect new sophisticated attacks — a deficiency pointed out in 2018 but never fixed. We shouldn’t have to rely on a private cybersecurity company to alert us of a major nation-state attack.

If anything, the US’s prioritization of offense over defense makes us less safe. In the interests of surveillance, the NSA has pushed for an insecure cell phone encryption standard and a backdoor in random number generators (important for secure encryption). The DoJ has never relented in its insistence that the world’s popular encryption systems be made insecure through back doors — another hot point where attack and defense are in conflict. In other words, we allow for insecure standards and systems, because we can use them to spy on others.

We need to adopt a defense-dominant strategy. As computers and the internet become increasingly essential to society, cyberattacks are likely to be the precursor to actual war. We are simply too vulnerable when we prioritize offense, even if we have to give up the advantage of using those insecurities to spy on others.

Our vulnerability is magnified as eavesdropping may bleed into a direct attack. The SVR’s access allows them not only to eavesdrop, but also to modify data, degrade network performance, or erase entire networks. The first might be normal spying, but the second certainly could be considered an act of war. Russia is almost certainly laying the groundwork for future attack.

This preparation would not be unprecedented. There’s a lot of attack going on in the world. In 2010, the US and Israel attacked the Iranian nuclear program. In 2012, Iran attacked the Saudi national oil company. North Korea attacked Sony in 2014. Russia attacked the Ukrainian power grid in 2015 and 2016. Russia is hacking the US power grid, and the US is hacking Russia’s power grid — just in case the capability is needed someday. All of these attacks began as a spying operation. Security vulnerabilities have real-world consequences.

We’re not going to be able to secure our networks and systems in this no-rules, free-for-all every-network-for-itself world. The US needs to willingly give up part of its offensive advantage in cyberspace in exchange for a vastly more secure global cyberspace. We need to invest in securing the world’s supply chains from this type of attack, and to press for international norms and agreements prioritizing cybersecurity, like the 2018 Paris Call for Trust and Security in Cyberspace or the Global Commission on the Stability of Cyberspace. Hardening widely used software like Orion (or the core internet protocols) helps everyone. We need to dampen this offensive arms race rather than exacerbate it, and work towards cyber peace. Otherwise, hypocritically criticizing the Russians for doing the same thing we do every day won’t help create the safer world in which we all want to live.

This essay previously appeared in the Guardian.

Impressive iPhone Exploit

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/12/impressive-iphone-exploit.html

This is a scarily impressive vulnerability:

Earlier this year, Apple patched one of the most breathtaking iPhone vulnerabilities ever: a memory corruption bug in the iOS kernel that gave attackers remote access to the entire device­ — over Wi-Fi, with no user interaction required at all. Oh, and exploits were wormable­ — meaning radio-proximity exploits could spread from one nearby device to another, once again, with no user interaction needed.

[…]

Beer’s attack worked by exploiting a buffer overflow bug in a driver for AWDL, an Apple-proprietary mesh networking protocol that makes things like Airdrop work. Because drivers reside in the kernel — ­one of the most privileged parts of any operating system­ — the AWDL flaw had the potential for serious hacks. And because AWDL parses Wi-Fi packets, exploits can be transmitted over the air, with no indication that anything is amiss.

[…]

Beer developed several different exploits. The most advanced one installs an implant that has full access to the user’s personal data, including emails, photos, messages, and passwords and crypto keys stored in the keychain. The attack uses a laptop, a Raspberry Pi, and some off-the-shelf Wi-Fi adapters. It takes about two minutes to install the prototype implant, but Beer said that with more work a better written exploit could deliver it in a “handful of seconds.” Exploits work only on devices that are within Wi-Fi range of the attacker.

There is no evidence that this vulnerability was ever used in the wild.

EDITED TO ADD: Slashdot thread.