Tag Archives: patching

Friday Squid Blogging: Unpatched Vulnerabilities in the Squid Caching Proxy

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2023/11/friday-squid-blogging-unpatched-vulnerabilities-in-the-squid-caching-proxy.html

In a rare squid/security post, here’s an article about unpatched vulnerabilities in the Squid caching proxy.

As usual, you can also use this squid post to talk about the security stories in the news that I haven’t covered.

Read my blog posting guidelines here.

BlackLotus Malware Hijacks Windows Secure Boot Process

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2023/03/blacklotus-malware-hijacks-windows-secure-boot-process.html

Researchers have discovered malware that “can hijack a computer’s boot process even when Secure Boot and other advanced protections are enabled and running on fully updated versions of Windows.”

Dubbed BlackLotus, the malware is what’s known as a UEFI bootkit. These sophisticated pieces of malware target the UEFI—short for Unified Extensible Firmware Interface—the low-level and complex chain of firmware responsible for booting up virtually every modern computer. As the mechanism that bridges a PC’s device firmware with its operating system, the UEFI is an OS in its own right. It’s located in an SPI-connected flash storage chip soldered onto the computer motherboard, making it difficult to inspect or patch. Previously discovered bootkits such as CosmicStrand, MosaicRegressor, and MoonBounce work by targeting the UEFI firmware stored in the flash storage chip. Others, including BlackLotus, target the software stored in the EFI system partition.

Because the UEFI is the first thing to run when a computer is turned on, it influences the OS, security apps, and all other software that follows. These traits make the UEFI the perfect place to launch malware. When successful, UEFI bootkits disable OS security mechanisms and ensure that a computer remains infected with stealthy malware that runs at the kernel mode or user mode, even after the operating system is reinstalled or a hard drive is replaced.

ESET has an analysis:

The number of UEFI vulnerabilities discovered in recent years and the failures in patching them or revoking vulnerable binaries within a reasonable time window hasn’t gone unnoticed by threat actors. As a result, the first publicly known UEFI bootkit bypassing the essential platform security feature—UEFI Secure Boot—is now a reality. In this blogpost we present the first public analysis of this UEFI bootkit, which is capable of running on even fully-up-to-date Windows 11 systems with UEFI Secure Boot enabled. Functionality of the bootkit and its individual features leads us to believe that we are dealing with a bootkit known as BlackLotus, the UEFI bootkit being sold on hacking forums for $5,000 since at least October 2022.


  • It’s capable of running on the latest, fully patched Windows 11 systems with UEFI Secure Boot enabled.
  • It exploits a more than one year old vulnerability (CVE-2022-21894) to bypass UEFI Secure Boot and set up persistence for the bootkit. This is the first publicly known, in-the-wild abuse of this vulnerability.
  • Although the vulnerability was fixed in Microsoft’s January 2022 update, its exploitation is still possible as the affected, validly signed binaries have still not been added to the UEFI revocation list. BlackLotus takes advantage of this, bringing its own copies of legitimate—but vulnerable—binaries to the system in order to exploit the vulnerability.
  • It’s capable of disabling OS security mechanisms such as BitLocker, HVCI, and Windows Defender.
  • Once installed, the bootkit’s main goal is to deploy a kernel driver (which, among other things, protects the bootkit from removal), and an HTTP downloader responsible for communication with the C&C and capable of loading additional user-mode or kernel-mode payloads.

This is impressive stuff.

Arresting IT Administrators

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/12/arresting-it-administrators.html

This is one way of ensuring that IT keeps up with patches:

Albanian prosecutors on Wednesday asked for the house arrest of five public employees they blame for not protecting the country from a cyberattack by alleged Iranian hackers.

Prosecutors said the five IT officials of the public administration department had failed to check the security of the system and update it with the most recent antivirus software.

The next step would be to arrest managers at software companies for not releasing patches fast enough. And maybe programmers for writing buggy code. I don’t know where this line of thinking ends.

Critical Microsoft Code-Execution Vulnerability

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/12/critical-microsoft-code-execution-vulnerability.html

A critical code-execution vulnerability in Microsoft Windows was patched in September. It seems that researchers just realized how serious it was (and is):

Like EternalBlue, CVE-2022-37958, as the latest vulnerability is tracked, allows attackers to execute malicious code with no authentication required. Also, like EternalBlue, it’s wormable, meaning that a single exploit can trigger a chain reaction of self-replicating follow-on exploits on other vulnerable systems. The wormability of EternalBlue allowed WannaCry and several other attacks to spread across the world in a matter of minutes with no user interaction required.

But unlike EternalBlue, which could be exploited when using only the SMB, or server message block, a protocol for file and printer sharing and similar network activities, this latest vulnerability is present in a much broader range of network protocols, giving attackers more flexibility than they had when exploiting the older vulnerability.


Microsoft fixed CVE-2022-37958 in September during its monthly Patch Tuesday rollout of security fixes. At the time, however, Microsoft researchers believed the vulnerability allowed only the disclosure of potentially sensitive information. As such, Microsoft gave the vulnerability a designation of “important.” In the routine course of analyzing vulnerabilities after they’re patched, Palmiotti discovered it allowed for remote code execution in much the way EternalBlue did. Last week, Microsoft revised the designation to critical and gave it a severity rating of 8.1, the same given to EternalBlue.

Apple Patches iPhone Zero-Day

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/12/apple-patches-iphone-zero-day.html

The most recent iPhone update—to version 16.1.2—patches a zero-day vulnerability that “may have been actively exploited against versions of iOS released before iOS 15.1.”


Apple said security researchers at Google’s Threat Analysis Group, which investigates nation state-backed spyware, hacking and cyberattacks, discovered and reported the WebKit bug.

WebKit bugs are often exploited when a person visits a malicious domain in their browser (or via the in-app browser). It’s not uncommon for bad actors to find vulnerabilities that target WebKit as a way to break into the device’s operating system and the user’s private data. WebKit bugs can be “chained” to other vulnerabilities to break through multiple layers of a device’s defenses.

Apple Only Commits to Patching Latest OS Version

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/10/apple-only-commits-to-patching-latest-os-version.html

People have suspected this for a while, but Apple has made it official. It only commits to fully patching the latest version of its OS, even though it claims to support older versions.

From ArsTechnica:

In other words, while Apple will provide security-related updates for older versions of its operating systems, only the most recent upgrades will receive updates for every security problem Apple knows about. Apple currently provides security updates to macOS 11 Big Sur and macOS 12 Monterey alongside the newly released macOS Ventura, and in the past, it has released security updates for older iOS versions for devices that can’t install the latest upgrades.

This confirms something that independent security researchers have been aware of for a while but that Apple hasn’t publicly articulated before. Intego Chief Security Analyst Joshua Long has tracked the CVEs patched by different macOS and iOS updates for years and generally found that bugs patched in the newest OS versions can go months before being patched in older (but still ostensibly “supported”) versions, when they’re patched at all.

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.

Responsible Disclosure for Cryptocurrency Security

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/09/responsible-disclosure-for-cryptocurrency-security.html

Stewart Baker discusses why the industry-norm responsible disclosure for software vulnerabilities fails for cryptocurrency software.

Why can’t the cryptocurrency industry solve the problem the way the software and hardware industries do, by patching and updating security as flaws are found? Two reasons: First, many customers don’t have an ongoing relationship with the hardware and software providers that protect their funds­—nor do they have an incentive to update security on a regular basis. Turning to a new security provider or using updated software creates risks; leaving everything the way it was feels safer. So users won’t be rushing to pay for and install new security patches.

Second, cryptocurrency is famously and deliberately decentralized, anonymized, and low friction. That means that the company responsible for hardware or software security may have no way to identify who used its product, or to get the patch to those users. It also means that many wallets with security flaws will be publicly accessible, protected only by an elaborate password. Once word of the flaw leaks, the password can be reverse engineered by anyone, and the legitimate owners are likely to find themselves in a race to move their assets before the thieves do. Even in the software industry, hackers routinely reverse engineer Microsoft’s patches to find the security flaws they fix and then try to exploit them before the patches have been fully installed.

He doesn’t have any good ideas to fix this. I don’t either. Just add it to the pile of blockchain’s many problems.

Java Cryptography Implementation Mistake Allows Digital-Signature Forgeries

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/04/java-cryptography-implementation-mistake-allows-digital-signature-forgeries.html

Interesting implementation mistake:

The vulnerability, which Oracle patched on Tuesday, affects the company’s implementation of the Elliptic Curve Digital Signature Algorithm in Java versions 15 and above. ECDSA is an algorithm that uses the principles of elliptic curve cryptography to authenticate messages digitally.


ECDSA signatures rely on a pseudo-random number, typically notated as K, that’s used to derive two additional numbers, R and S. To verify a signature as valid, a party must check the equation involving R and S, the signer’s public key, and a cryptographic hash of the message. When both sides of the equation are equal, the signature is valid.


For the process to work correctly, neither R nor S can ever be a zero. That’s because one side of the equation is R, and the other is multiplied by R and a value from S. If the values are both 0, the verification check translates to 0 = 0 X (other values from the private key and hash), which will be true regardless of the additional values. That means an adversary only needs to submit a blank signature to pass the verification check successfully.

Madden wrote:

Guess which check Java forgot?

That’s right. Java’s implementation of ECDSA signature verification didn’t check if R or S were zero, so you could produce a signature value in which they are both 0 (appropriately encoded) and Java would accept it as a valid signature for any message and for any public key. The digital equivalent of a blank ID card.

More details.

Vendors are Fixing Security Flaws Faster

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/02/vendors-are-fixing-security-flaws-faster.html

Google’s Project Zero is reporting that software vendors are patching their code faster.


  • In 2021, vendors took an average of 52 days to fix security vulnerabilities reported from Project Zero. This is a significant acceleration from an average of about 80 days 3 years ago.
  • In addition to the average now being well below the 90-day deadline, we have also seen a dropoff in vendors missing the deadline (or the additional 14-day grace period). In 2021, only one bug exceeded its fix deadline, though 14% of bugs required the grace period.
  • Differences in the amount of time it takes a vendor/product to ship a fix to users reflects their product design, development practices, update cadence, and general processes towards security reports. We hope that this comparison can showcase best practices, and encourage vendors to experiment with new policies.
  • This data aggregation and analysis is relatively new for Project Zero, but we hope to do it more in the future. We encourage all vendors to consider publishing aggregate data on their time-to-fix and time-to-patch for externally reported vulnerabilities, as well as more data sharing and transparency in general.

More Log4j News

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2021/12/more-log4j-news.html

Log4j is being exploited by all sorts of attackers, all over the Internet:

At that point it was reported that there were over 100 attempts to exploit the vulnerability every minute. “Since we started to implement our protection we prevented over 1,272,000 attempts to allocate the vulnerability, over 46% of those attempts were made by known malicious groups,” said cybersecurity company Check Point.

And according to Check Point, attackers have now attempted to exploit the flaw on over 40% of global networks.

And a second vulnerability was found, in the patch for the first vulnerability. This is likely not to be the last.

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.

Paragon: Yet Another Cyberweapons Arms Manufacturer

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2021/08/paragon-yet-another-cyberweapons-arms-manufacturer.html

Forbes has the story:

Paragon’s product will also likely get spyware critics and surveillance experts alike rubbernecking: It claims to give police the power to remotely break into encrypted instant messaging communications, whether that’s WhatsApp, Signal, Facebook Messenger or Gmail, the industry sources said. One other spyware industry executive said it also promises to get longer-lasting access to a device, even when it’s rebooted.


Two industry sources said they believed Paragon was trying to set itself apart further by promising to get access to the instant messaging applications on a device, rather than taking complete control of everything on a phone. One of the sources said they understood that Paragon’s spyware exploits the protocols of end-to-end encrypted apps, meaning it would hack into messages via vulnerabilities in the core ways in which the software operates.

Read that last sentence again: Paragon uses unpatched zero-day exploits in the software to hack messaging apps.

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.

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.

On Vulnerability-Adjacent Vulnerabilities

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2021/02/on-vulnerability-adjacent-vulnerabilities.html

At the virtual Enigma Conference, Google’s Project Zero’s Maggie Stone gave a talk about zero-day exploits in the wild. In it, she talked about how often vendors fix vulnerabilities only to have the attackers tweak their exploits to work again. From a MIT Technology Review article:

Soon after they were spotted, the researchers saw one exploit being used in the wild. Microsoft issued a patch and fixed the flaw, sort of. In September 2019, another similar vulnerability was found being exploited by the same hacking group.

More discoveries in November 2019, January 2020, and April 2020 added up to at least five zero-day vulnerabilities being exploited from the same bug class in short order. Microsoft issued multiple security updates: some failed to actually fix the vulnerability being targeted, while others required only slight changes that required just a line or two to change in the hacker’s code to make the exploit work again.


“What we saw cuts across the industry: Incomplete patches are making it easier for attackers to exploit users with zero-days,” Stone said on Tuesday at the security conference Enigma. “We’re not requiring attackers to come up with all new bug classes, develop brand new exploitation, look at code that has never been researched before. We’re allowing the reuse of lots of different vulnerabilities that we previously knew about.”


Why aren’t they being fixed? Most of the security teams working at software companies have limited time and resources, she suggests — and if their priorities and incentives are flawed, they only check that they’ve fixed the very specific vulnerability in front of them instead of addressing the bigger problems at the root of many vulnerabilities.

Another article on the talk.

This is an important insight. It’s not enough to patch existing vulnerabilities. We need to make it harder for attackers to find new vulnerabilities to exploit. Closing entire families of vulnerabilities, rather than individual vulnerabilities one at a time, is a good way to do that.

Backdoor in Zyxel Firewalls and Gateways

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2021/01/backdoor-in-zyxel-firewalls-and-gateways.html

This is bad:

More than 100,000 Zyxel firewalls, VPN gateways, and access point controllers contain a hardcoded admin-level backdoor account that can grant attackers root access to devices via either the SSH interface or the web administration panel.


Installing patches removes the backdoor account, which, according to Eye Control researchers, uses the “zyfwp” username and the “PrOw!aN_fXp” password.

“The plaintext password was visible in one of the binaries on the system,” the Dutch researchers said in a report published before the Christmas 2020 holiday.