A modchip described in the article - a small PCB with an epoxy blob on it, soldered to the Cisco switch PCB using four thin wires

Counterfeit Cisco Hardware Bypasses Security Checks With Modchips

February 1, 2023 by Arya Voronova 32 Comments

Some pictures recently surfaced on social media, showing a small PCB tapped into four points on Cisco-branded boards. What is this about? A NSA backdoor so data can be exfiltrated to some third party? Well, that’s theoretically possible, but it’s actually used for bypassing hardware authenticity checks in Cisco hardware being cloned — a sizable industry. Of course, “can’t believe it’s not Cisco” hardware is only valuable insofar that it’s able to run the Cisco software, and that’s where the bodge boards play a major role.

A 2020 report by F-Secure details an investigation, comparing three switches marked as Cisco 2960X – one known genuine and two known counterfeits. The counterfeits had the aforementioned implants either soldered to the bottom of the PCB or added to the board as a separate component, and the paper goes into why they’re important for successful counterfeiting.

Apparently, these chips emulate or bypass an I2C EEPROM containing part of the code executed during the boot sequence, and Cisco depends on this EEPROM’s contents for authenticity verification. Cisco software reads the EEPROM twice — once for verification, and once again for actually running it. The microcontroller included on the mod board can return a genuine binary with a valid signature on the first read, and a binary with hardware checks patched out for subsequent reads.

The paper will tell you about way more than this — it’s thorough yet captivating. As you’d expect, it devotes quite a bit of time to comparing genuine and counterfeit boards, showing that the cloning process is pretty to-the-T, save for some part substitutions. For instance, check out the PDF page 12 to see how via locations are exactly copied between PCBs in a bizarre way, or the Cisco file format and authenticity check analysis closer to the end of the report. All in all, the 38 pages of the document make for a fun foray into what makes Cisco authentication mechanisms tick, and what helps clone hardware makers bypass them.

Are such chips ever used for adding backdoors and data exfiltration? There’s no evidence of that, as much as that’s not to be excluded — bypassing anti-cloning protections would make other hijinks more viable no doubt, that said, only hardware authentication bypass measures were found so far. This mechanism also breaks during software updates, and absolutely, leaves some to be desired when it comes to its stated functionality. That said, such fun insights can help us, say, enforce right-to-repair, enable hardware reuse, and thwart many predatory business practices in areas where laws fail us.

Opening A Safe With A Stepper Motor And DIY Auto-Dialer

January 29, 2023 by Maya Posch 24 Comments

What do you do when you happen to come into possession of a safe of which the combination is lost to the sands of time? If you’re someone like [eNBeWe], you grab a stepper motor with driver module you had lying around gathering dust, an ESP8266 for the brains and a few other pieces to build your very own auto-dialer to crack that safe combination. The software has been made available on GitHub for those interested.

While other auto-dialers used with the fun hobby of safe cracking can generally find the combination in a matter of hours if not less, it took [eNBeWe]’s contraption two days to crack the combination. Much of this was due to the hacked together nature of the structure, with the glue joints among other weak points that’d probably not take too kindly to a lot of abuse. Since there was no particular rush to get into the safe, this worked out fine.

As an impromptu auto-dialer thrown together with parts that were lying around it seemed to perform just fine for the task, and we presume that this is the beginning of a beautiful new lock- and safe-picking hobby.

Continue reading “Opening A Safe With A Stepper Motor And DIY Auto-Dialer” →

This Week In Security: GTA, Apple And Android, And Insecure Boot

January 27, 2023 by Jonathan Bennett 11 Comments

When we first saw tweets about a security issue in Grand Theft Auto V, it sounded a bit like a troll. “Press ‘alt and f4’ to unlock a cheat mode”, or the hacker that claims to be able to delete your character. [Tez2]’s warning tweet that you shouldn’t play GTA Online without a firewall sounds like another of these online urban legends. But this one actually seems legit. NIST is even in on the fun, assigning CVE-2023-24059 for the exploit.

When playing an online game, other users send a “join request” to join the active session. This packets can contain malformed data which has been observed to crash the game client remotely. It’s believed, though not publicly confirmed, that it’s also a Remote Code Execution (RCE) vulnerability. It seems likely that this aspect will be added to some of the various cheat panels that are already widely used for this 10-year-old game. So now, rather than just giving your own character infinite ammo and health, you can inflict some havoc on other players, possibly up to corrupting their character files and getting them banned.

But why stop there? If we have code execution inside the game, what stops another player from launching a real attack? A video game isn’t sandboxed like a browser, and there’s nothing preventing a disk wiper attack or even a worm from compromising a bunch of players. The worst part is that it’s an old game, and even though there’s a large playerbase, it’s not guaranteed to get a fix. There’s at least one project aiming to be a firewall to prevent the issue. Continue reading “This Week In Security: GTA, Apple And Android, And Insecure Boot” →

Four images in one. Top left is an image of four individuals in a room with whiteboards and desks in the background along with various clutter on the floor. Over the people is a wireframe overlay of their poses. The image on the top right is just the wireframe people on a black background. Bottom left image is of a single individual standing in a room with the pose wireframe overlay. Bottom right image is the single pose wireframe on a black background.

Tracking Humans With WiFi

January 26, 2023 by Navarre Bartz 45 Comments

In case you thought that cameras, LiDAR, infrared sensors, and the like weren’t enough for Big Brother to track you, researchers from Carnegie Mellon University have found a way to track human movements via WiFi. [PDF via VPNoverview]

The process uses the signals from WiFi routers for an inexpensive way to determine human poses that isn’t hampered by lack of illumination or object occlusion. The system produces UV coordinates of human bodies by analyzing signal strength and phase data to generate a 2D feature map and then feeding that through a modified DensePose-RCNN architecture which corresponds to 3D human poses. The system does have trouble with unusual poses that are not in the training set or if there are more than three subjects in the detection area.

While there are probably applications in Kinect-esque VR Halo games, this will probably go straight into the toolbox of three letter agencies and advertising-fueled tech companies. The authors claim this to use “privacy-preserving algorithms for human sensing,” but only time will tell if they’re correct.

If you’re interested in other creepy surveillance tools, checkout the Heat-Sensing Crotch Monitor or this Dystopian Peep Show.

An illustration of a key sitting on an ID card. The key is light grey and the ID card is a darker grey gradient. The ID card says ID-1 Card 85.60 by 53.98 mm

All Your Keys Are Belong To KeyDecoder

January 21, 2023 by Navarre Bartz 56 Comments

Physical security is often considered simpler than digital security since safes are heavy and physical keys take more effort to duplicate than those of the digital persuasion. [Maxime Beasse and Quentin Clement] have developed a smartphone app that can duplicate a key from a photo making key copying much easier.

KeyDecoder is an open source Android app that can generate all the necessary bitting info to duplicate a key from just an image. Luckily for the paranoid among us, the image must be taken with the key laying flat without a keyring on an ISO/CEI 7810 ID-1 ID or credit card. A passerby can’t just snap a photo of your keys across the room and go liberate your home furnishings, but it still would be wise to keep a closer eye on your keys now that this particular ~~cat~~ hack is out of the bag.

The project’s GitHub page is awash in warnings that this tool is designed solely for “pentesters and security enthusiasts” to warn their friends and clients about the dangers of leaving their keys exposed. After learning about this tool, we wouldn’t be surprised if some in the audience start rethinking how they carry and store their physical keys from now on.

If you want to see some more hacks to duplicate keys, checkout Copying High Security Keys With OpenSCAD And Light and Methods Of Copying High Security Keys.

This Week In Security: Git Deep Dive, Mailchimp, And SPF

January 20, 2023 by Jonathan Bennett 10 Comments

First up, git has been audited. This was an effort sponsored by the Open Source Technology Improvement Fund (OSTIF), a non-profit working to improve the security of Open Source projects. The audit itself was done by researchers from X41 and GitLab, and two critical vulnerabilities were found, both caused by the same bad coding habit — using an int to hold buffer lengths.

On modern systems, a size_t is always unsigned, and the same bit length as the architecture bit-width. This is the proper data type for string and buffer lengths, as it is guaranteed not to overflow when handling lengths up to the maximum addressable memory on the system. On the other hand, an int is usually four bytes long and signed, with a maximum value of 2^31-1, or 2147483647 — about 2 GB. A big buffer, but not an unheard amount of data. Throw something that large at git, and it will break in unexpected ways.

Our first example is CVE-2022-23521, an out of bounds write caused by an int overflowing to negative. A .gitattributes file can be committed to a repository with a modified git client, and then checking out that repository will cause the num_attrs variable to overflow. Push the overflow all the way around to a small negative number, and git will then vastly under-allocate the attributes buffer, and write all that data past the end of the allocated buffer.

CVE-2022-41903 is another signed integer overflow, this time when a pretty print format gets abused to do something unexpected. Take a look at this block of code:

Continue reading “This Week In Security: Git Deep Dive, Mailchimp, And SPF” →

This Week In Security: Cacti RCE, VMs In The Browser, And SugarCRM

January 13, 2023 by Jonathan Bennett 7 Comments

This week we start with a Remote Code Execution (RCE) vulnerability that has potential to be a real pain for sysadmins. Cacti, the system monitoring and graphing solution, has a pair of bugs that chain together to allow an attacker with unauthenticated access to the HTTP/S port to trivially execute bash commands. The first half of this attack is an authentication bypass, and it’s embarrassingly trivial. The Cacti authentication code trusts the Forwarded-For: header in the request. Set it to the server’s IP, and the authentication code treats it like a localhost request, bypassing any real authentication process.

The second half is found in the remote_agent.php endpoint, where the poller_id is set by the user and treated as a string. Then, if the right host_id and local_data_id item is triggered, that string is concatenated into a proc_open() function call. The string isn’t sanitized, so it’s trivial enough to include a second command to run, dropping a webshell, for instance.

Version 1.2.23 of Cacti contains the fix, and released on the 2nd. This one is likely to be exploited, and if automated exploitation hasn’t started already, it likely will soon. So if you have a Cacti install, go double-check that the interface isn’t exposed to the world.

JSON Web Token

Researchers at Unit 42 found an exploit that can be used to achieve an RCE in the JsonWebToken project. The issue is this library’s verify() function, which takes arguments of the token to check, the key to use, and options. If there aren’t any algorithms specified in the options object, then the key is processed as a PEM string. The toString() method of that key is called during the actual check, and the assumption is that it’s either a string or buffer. But what if the key passed in to the verify() function was actually a complex object, bringing it’s own toString() method along to play. At that point, we have arbitrary code execution. And if this code is running on the server-side under node.js, that means a popped server.

But wait, it’s not that simple, right? It’s not like a valid JWT can contain an arbitrary object — that would be a problem all on its own. So CVE-2022-23529 is a stepping-stone. It’s insecure code, but the rest of the application has to have another vulnerability for this one to be reachable. Continue reading “This Week In Security: Cacti RCE, VMs In The Browser, And SugarCRM” →