This Week in Security

270 Articles

This Week In Security: Trains, Fake Homebrew, And AI Auto-Hacking

July 18, 2025 by 5 Comments

There’s a train vulnerability making the rounds this week. The research comes from [midwestneil], who first discovered an issue way back in 2012, and tried to raise the alarm.

To understand the problem, we have to first talk about the caboose. The caboose was the last car in the train, served as an office for the conductor, and station for train workers to work out of while tending to the train and watching for problems. Two more important details about the caboose, is that it carried the lighted markers to indicate the end of the train, and was part of the train’s breaking system. In the US, in the 1980s, the caboose was phased out, and replaced with automated End Of Train (EOT) devices.

These devices were used to wirelessly monitor the train’s air brake system, control the Flashing Rear End Device (FRED), and even trigger the brakes in an emergency. Now here’s the security element. How did the cryptography on that wireless signal work in the 1980s? And has it been updated since then?

The only “cryptography” at play in the FRED system is a BCH checksum, which is not an encryption or authentication tool, but an error correction algorithm. And even though another researcher discovered this issue and reported it as far back as 2005, the systems are still using 1980s era wireless systems. Now that CISA and various news outlets have picked on the vulnerability, the Association of American Railroads are finally acknowledging it and beginning to work on upgrading.

Putting GitHub Secrets to Work

We’ve covered GitHub secret mining several times in this column in the past. This week we cover research from GitGuardian and Synacktiv, discovering how to put one specific leaked secret to use. The target here is Laravel, an Open Source PHP framework. Laravel is genuinely impressive, and sites built with this tool use an internal APP_KEY to encrypt things like cookies, session keys, and password reset tokens.

Laravel provides the encrypt() and decrypt() functions to make that process easy. The decrypt() function even does the deserialization automatically. … You may be able to see where this is going. If an attacker has the APP_KEY, and can convince a Laravel site to decrypt arbitrary data, there is likely a way to trigger remote code execution through a deserialization attack, particularly if the backend isn’t fully up to date.

So how bad is the issue? By pulling from their records of GitHub, GitGuardian found 10,000 APP_KEYs. 1,300 of which also included URLs, and 400 of those could actually be validated as still in use. The lesson here is once again, when you accidentally push a secret to Github (or anywhere on the public Internet), you must rotate that secret. Just force pushing over your mistake is not enough.

Fake Homebrew

There’s a case to be made that browsers should be blocking advertisements simply for mitigating the security risk that comes along with ads on the web. Case in point is the fake Homebrew install malware. This write-up comes from the security team at Deriv, where a MacOS device triggered the security alarms. The investigation revealed that an employee was trying to install Homebrew, searched for the instructions, and clicked on a sponsored result in the search engine. This led to a legitimate looking GitHub project containing only a readme with a single command to automatically install Homebrew.

The command downloads and runs a script that does indeed install Homebrew. It also prompts for and saves the user’s password, and drops a malware loader. This story has a happy ending, with the company’s security software catching the malware right away. This is yet another example of why it’s foolhardy to run commands from the Internet without knowing exactly what they do. Not to mention, this is exactly the scenario that led to the creation of Workbrew.

SQL Injection

Yes, it’s 2025, and we’re still covering SQL injections. This vulnerability in Fortinet’s Fortiweb Fabric Connector was discovered independently by [0x_shaq] and the folks at WatchTowr. The flaw here is the get_fabric_user_by_token() function, which regrettably appends the given token directly to a SQL query. Hence the Proof of Concept:

GET /api/fabric/device/status HTTP/1.1
Host: 192.168.10.144
Authorization: Bearer 123'//or//'x'='x

And if the simple injection wasn’t enough, the watchTowr write-up manages a direct Remote Code Execution (RCE) from an unauthenticated user, via a SQL query containing an os.system() call. And since MySQL runs as root on these systems, that’s pretty much everything one could ask for.

AI guided AI attacks

The most intriguing story from this week is from [Golan Yosef], describing a vibe-researching session with the Claude LLM. The setup is a Gmail account and the Gmail MCP server to feed spammy emails into Claude desktop, and the Shell MCP server installed on that machine. The goal is to convince Claude to take some malicious action in response to an incoming, unsolicited email. The first attempt failed, and in fact the local Claude install warned [Golan] that the email may be a phishing attack. Where this mildly interesting research takes a really interesting turn, is when he asked Claude if such an attack could ever work.

Claude gave some scenarios where such an attack might succeed, and [Golan] pointed out that each new conversation with Claude is a blank slate. This led to a bizarre exchange where the running instance of Claude would play security researcher, and write emails intended to trick another instance of Claude into doing something it shouldn’t. [Golan] would send the emails to himself, collect the result, and then come back and tell Researcher Claude what happened. It’s quite the bizarre scenario. And it did eventually work. After multiple tries, Claude did write an email that was able to coerce the fresh instance of Claude to manipulate the file system and run calc.exe. This is almost the AI-guided fuzzing that is inevitably going to change security research. It would be interesting to automate the process, so [Golan] didn’t have to do the busywork of shuffling the messages between the two iterations of Claude. I’m confident we’ll cover many more stories in this vein in the future.

Bits and Bytes

SugarCRM fixed a LESS code injection in an unauthenticated endpoint. These releases landed in October of last year, in versions 13.0.4 and 14.0.1. While there isn’t any RCE at play here, this does allow Server-Side Request Forgery, or arbitrary file reads.

Cryptojacking is the technique where a malicious website embeds a crypto miner in the site. And while it was particularly popular in 2017-2019, browser safeguards against blatant cryptojacking put an end to the practice. What c/side researchers discovered is that cryptojacking is still happening, just very quietly.

There’s browser tidbits to cover in both major browsers. In Chrome it’s a sandbox escape paired with a Windows NT read function with a race condition, that makes it work as a write primitive. To actually make use of it, [Vincent Yeo] needed a Chrome sandbox escape.

ZDI has the story of Firefox and a JavaScript Math confusion attack. By manipulating the indexes of arrays and abusing the behavior when integer values wrap-around their max value, malicious code could read and write to memory outside of the allocated array. This was used at Pwn2Own Berlin earlier in the year, and Firefox patched the bug on the very next day. Enjoy!

This Week In Security: Bitchat, CitrixBleed Part 2, Opossum, And TSAs

July 11, 2025 by 10 Comments

@jack is back with a weekend project. Yes, that Jack. [Jack Dorsey] spent last weekend learning about Bluetooth meshing, and built Bitchat, a BLE mesh encrypted messaging application. It uses X25519 for key exchange, and AES-GCM for message encryption. [Alex Radocea] took a look at the current state of the project, suspects it was vibe coded, and points out a glaring problem with the cryptography.

So let’s take a quick look at the authentication and encryption layer of Bitchat. The whitepaper is useful, but still leaves out some of the important details, like how the identity key is tied to the encryption keys. The problem here is that it isn’t.

Bitchat has, by necessity, a trust-on-first-use authentication model. There is intentionally no authentication central authority to verify the keys of any given user, and the application hasn’t yet added an out-of-band authentication method, like scanning QR codes. Instead, it has a favorites system, where the user can mark a remote user as a favorite, and the app saves those keys forever. There isn’t necessarily anything wrong with this approach, especially if users understand the limitations.

The other quirk is that Bitchat uses ephemeral keys for each chat session, in an effort to have some forward secrecy. In modern protocols, it’s desirable to have some protection against a single compromised encryption key exposing all the messages in the chain. It appears that Bitchat accomplishes this by generating dedicated encryption keys for each new chat session. But those ephemeral keys aren’t properly verified. In fact, they aren’t verified by a user’s identity key at all!

The attack then, is to send a private message to another user, present the public key of whoever your’re trying to impersonate, and include new ephemeral encryption keys. Even if your target has this remote user marked as a favorite, the new encryption keys are trusted. So the victim thinks this is a conversation with a trusted person, and it’s actually a conversation with an attacker. Not great. Continue reading “This Week In Security: Bitchat, CitrixBleed Part 2, Opossum, And TSAs” →

This Week In Security: Anthropic, Coinbase, And Oops Hunting

July 7, 2025 by 8 Comments

Anthropic has had an eventful couple weeks, and we have two separate write-ups to cover. The first is a vulnerability in the Antropic MCP Inspector, CVE-2025-49596. We’ve talked a bit about the Module Context Protocol (MCP), the framework that provides a structure for AI agents to discover and make use of software tools. MCP Inspector is an Open Source tool that proxies MCP connections, and provides debugging information for developers.

MCP Inspector is one of those tools that is intended to be run only on secure networks, and doesn’t implement any security or authentication controls. If you can make a network connection to the tool, you can control it. and MCP Inspector has the /sse endpoint, which allows running shell commands as a feature. This would all be fine, so long as everyone using the tool understands that it is not to be exposed to the open Internet. Except there’s another security quirk that intersects with this one. The 0.0.0.0 localhost bypass.

The “0.0.0.0 day exploit” is a bypass in essentially all the modern browsers, where localhost can be accessed on MacOS and Linux machines by making requests to 0.0.0.0. Browsers and security programs already block access to localhost itself, and 127.0.0.1, but this bypass means that websites can either request 0.0.0.0 directly, or rebind a domain name to 0.0.0.0, and then make requests.

Continue reading “This Week In Security: Anthropic, Coinbase, And Oops Hunting” →

This Week In Security: MegaOWNed, Store Danger, And FileFix

June 27, 2025 by 7 Comments

Earlier this year, I was required to move my server to a different datacenter. The tech that helped handle the logistics suggested I assign one of my public IPs to the server’s Baseboard Management Controller (BMC) port, so I could access the controls there if something went sideways. I passed on the offer, and not only because IPv4 addresses are a scarce commodity these days. No, I’ve never trusted a server’s built-in BMC. For reasons like this MegaOWN of MegaRAC, courtesy of a CVSS 10.0 CVE, under active exploitation in the wild.

This vulnerability was discovered by Eclypsium back in March and it’s a pretty simple authentication bypass, exploited by setting an X-Server-Addr header to the device IP address and adding an extra colon symbol to that string. Send this along inside an HTTP request, and it’s automatically allowed without authentication. This was assigned CVE-2024-54085, and for servers with the BMC accessible from the Internet, it scores that scorching 10.0 CVSS.

We’re talking about this now, because CISA has added this CVE to the official list of vulnerabilities known to be exploited in the wild. And it’s hardly surprising, as this is a near-trivial vulnerability to exploit, and it’s not particularly challenging to find web interfaces for the MegaRAC devices using tools like Shodan and others.

There’s a particularly ugly scenario that’s likely to play out here: Embedded malware. This vulnerability could be chained with others, and the OS running on the BMC itself could be permanently modified. It would be very difficult to disinfect and then verify the integrity of one of these embedded systems, short of physically removing and replacing the flash chip. And malware running from this very advantageous position very nearly have the keys to the kingdom, particularly if the architecture connects the BMC controller over the PCIe bus, which includes Direct Memory Access.

This brings us to the really bad news. These devices are everywhere. The list of hardware that ships with the MegaRAC Redfish UI includes select units from “AMD, Ampere Computing, ASRock, ARM, Fujitsu, Gigabyte, Huawei, Nvidia, Supermicro, and Qualcomm”. Some of these vendors have released patches. But at this point, any of the vulnerable devices on the Internet, still unpatched, should probably be considered compromised. Continue reading “This Week In Security: MegaOWNed, Store Danger, And FileFix” →

This Week In Security: That Time I Caused A 9.5 CVE, IOS Spyware, And The Day The Internet Went Down

June 20, 2025 by 18 Comments

Meshtastic just released an eye-watering 9.5 CVSS CVE, warning about public/private keys being re-used among devices. And I’m the one that wrote the code. Not to mention, I triaged and fixed it. And I’m part of Meshtastic Solutions, the company associated with the project. This is is the story of how we got here, and a bit of perspective.

First things first, what kind of keys are we talking about, and what does Meshtastic use them for? These are X25519 keys, used specifically for encrypting and authenticating Direct Messages (DMs), as well as optionally for authorizing remote administration actions. It is, by the way, this remote administration scenario using a compromised key, that leads to such a high CVSS rating. Before version 2.5 of Meshtastic, the only cryptography in place was simple AES-CTR encryption using shared symmetric keys, still in use for multi-user channels. The problem was that DMs were also encrypted with this channel key, and just sent with the “to” field populated. Anyone with the channel key could read the DM.

I re-worked an old pull request that generated X25519 keys on boot, using the rweather/crypto library. This sentence highlights two separate problems, that both can lead to unintentional key re-use. First, the keys are generated at first boot. I was made painfully aware that this was a weakness, when a user sent an email to the project warning us that he had purchased two devices, and they had matching keys out of the box. When the vendor had manufactured this device, they flashed Meshtastic on one device, let it boot up once, and then use a debugger to copy off a “golden image” of the flash. Then every other device in that particular manufacturing run was flashed with this golden image — containing same private key. sigh

Continue reading “This Week In Security: That Time I Caused A 9.5 CVE, IOS Spyware, And The Day The Internet Went Down” →

This Week In Security: The Localhost Bypass, Reflections, And X

June 13, 2025 by 26 Comments

Facebook and Yandex have been caught performing user-hostile tracking. This sort of makes today just another Friday, but this is a bit special. This time, it’s Local Mess. OK, it’s an attack with a dorky name, but very clever. The short explanation is that web sites can open connections to localhost. And on Android, apps can be listening to those ports, allowing web pages to talk to apps.

That may not sound too terrible, but there’s a couple things to be aware of. First, Android (and iOS) apps are sandboxed — intentionally making it difficult for one app to talk to another, except in ways approved by the OS maker. The browser is similarly sandboxed away from the apps. This is a security boundary, but it is especially an important security boundary when the user is in incognito mode.

The tracking Pixel is important to explain here. This is a snippet of code, that puts an invisible image on a website, and as a result allows the tracker to run JavaScript in your browser in the context of that site. Facebook is famous for this, but is not the only advertising service that tracks users in this way. If you’ve searched for an item on one site, and then suddenly been bombarded with ads for that item on other sites, you’ve been tracked by the pixel.

This is most useful when a user is logged in, but on a mobile device, the user is much more likely to be logged in on an app and not the browser. The constant pressure for more and better data led to a novel and completely unethical solution. On Android, applications with permission to access the Internet can listen on localhost (127.0.0.1) on unprivileged ports, those above 1024.

Facebook abused this quirk by opening a WebRTC connection to localhost, to one of the ports the Facebook app was listening on. This triggers an SDP connection to localhost, which starts by sending a STUN packet, a UDP tool for NAT traversal. Packed into that STUN packet is the contents of a Facebook Cookie, which the Facebook app happily forwards up to Facebook. The browser also sends that cookie to Facebook when loading the pixel, and boom Facebook knows what website you’re on. Even if you’re not logged in, or incognito mode is turned on.

Yandex has been doing something similar since 2017, though with a different, simpler mechanism. Rather than call localhost directly, Yandex just sets aside yandexmetrica.com for this purpose, with the domain pointing to 127.0.0.1. This was just used to open an HTTP connection to the native Yandex apps, which passed the data up to Yandex over HTTPS. Meta apps were first seen using this trick in September 2024, though it’s very possible it was in use earlier.

Both companies have ceased since this report was released. What’s interesting is that this is a flagrant violation of GDPR and CCPA, and will likely lead to record-setting fines, at least for Facebook.

Continue reading “This Week In Security: The Localhost Bypass, Reflections, And X” →

This Week In Security: Roundcube, Unified Threat Naming, And AI Chat Logs

June 6, 2025 by 4 Comments

Up first, if you’re running a Roundcube install prior to 1.5.10 or 1.6.11, it’s time to update. We have an authenticated Remote Code Execution (RCE) in the Roundcube Webmail client. And while that’s not quite the level of chaos that an unauthenticated RCE would cause, it’s still to be taken seriously. Mainly because for the majority of the 53 million Roundcube installs out there, the users aren’t entirely trusted.

The magic at play in this vulnerability is the Roundcube user session code, and specifically the session deserialization scheme. There’s a weird code snippet in the unserialize function:
if ($str[$p] == '!') {
$p++;
$has_value = false;

The exclamation mark makes the code skip a character, and then assume that what comes next has no value. But if it does actually have a value, well then you’ve got a slightly corrupted deserialization, resulting in a slightly corrupted session. This really comes into force when combined with the file upload function, as the uploaded filename serves as a payload delivery mechanism. Use the errant exclamation mark handling to throw off deserialization, and the filename can contain arbitrary session key/value pairs. A GPG class from the PEAR library allows running an arbitrary command, and this can be hijacked with the session manipulation. Continue reading “This Week In Security: Roundcube, Unified Threat Naming, And AI Chat Logs” →