Security Hacks

1393 Articles

USB HID And Run Exposes Yet Another BadUSB Surface

April 4, 2024 by 20 Comments

You might think you understand the concept of BadUSB attacks and know how to defend it, because all you’ve seen is opening a terminal window. Turns out there’s still more attack surface to cover, as [piraija] tells us in their USB-HID-and-run publication. If your system doesn’t do scrupulous HID device filtering, you might just be vulnerable to a kind of BadUSB attack you haven’t seen yet, rumoured to have been the pathway a few ATMs got hacked – simply closing the usual BadUSB routes won’t do.

The culprit is the Consumer Control specification – an obscure part of HID standard that defines media buttons, specifically, the “launch browser” and “open calculator” kinds of buttons you see on some keyboards, that operating systems, surprisingly, tend to support. If the underlying OS you’re using for kiosk purposes isn’t configured to ignore these buttons, they provide any attacker with unexpected pathways to bypass your kiosk environment, and it works astonishingly well.

[piraija] tells us that this attack provides us with plenty of opportunities, having tested it on a number of devices in the wild. For your own tests, the writeup has Arduino example code you can upload onto any USB-enabled microcontroller, and for better equipped hackers out there, we’re even getting a Flipper Zero application you can employ instead. While we’ve seen some doubts that USB devices can be a proper attack vector, modern operating systems are more complex and bloated than even meets the eye, often for hardly any reason – for example, if you’re on Windows 10 or 11, press Ctrl+Shift+Alt+Win+L and behold. And, of course, you can make a hostile USB implant small enough that you can build them into a charger or a USB-C dock.

USB image: Inductiveload, Public domain.

The printer's display with the exploit-loaded animation playing, saying "hacked by blasty" and a bunch more stuff

A Fun Exploit For Canon Printers Brings GDB Gifts

April 4, 2024 by 12 Comments

Modern printers make it all that much more tempting to try and hack them — the hardware generally tends to be decent, but the firmware appears to be designed to squeeze as much money out of you as possible while keeping your annoyance level consistently high. That’s why it’s nice to see this exploit of the Canon imageCLASS MF74XCdw series (MF742Cdw/MF743Cdw) by [blasty], triggerable over a network connection, with a story for our amusement.

In this post, we get a tale of how this hack came out of a Pwn2Own Toronto challenge, notes on the hardware involved, and we’re shown the journey to a successful hack. The Canon printer OS is built without many of the protections, which makes playing with it easier than with more modernized targets, but it’s nevertheless not straightforward. Still, exploiting a couple things like the SOAP XML implementation and the UTF8 encoder nets you an ability to play nice animations on the display, and most certainly, control over the entirety of the hardware if you wanted it.

One of the most fun things about this hack is the GDB stub recently included in the repo. If you wanted to debug Canon printers for fun or profit, [blasty] brings you a GDB stub to do that comfortably, with a respectable README that even has porting notes for other Canon ImageCLASS printer models, should you lay your hands on a different machine of despair. WiFi connectivity appears to be enough for this hack, so you better make sure you don’t have your network-connected printers exposed on the Internet — not that you needed more reasons to avoid that.

Three ZigBee radios in ESD bags, marked "Zigbee Sniffer", "Router" and "Coordinator".

Crash IoT Devices Through Protocol Fuzzing

April 2, 2024 by 1 Comment

IoT protocols are a relatively unexplored field compared to most PC-exposed protocols – it’s bothersome to need a whole radio setup before you can tinker on something, and often, for low-level experiments, just any radio won’t do. This means there’s quite a bit of security ground to cover. Now, the U-Fuzz toolkit from [asset-group] helps us make up for it.

Unlike fuzzers you might imagine, U-Fuzz doesn’t go in blindly. This toolkit has provisions to parse protocols and fuzz fields meaningfully, which helps because many of devices will discard packets they deem too malformed. With U-Fuzz, you feed it a couple packet captures, help it make some conclusions about packet and protocol structure, and get suggestions on how to crash your devices in ways not yet foreseen.

This allows for basically arbitrary protocol fuzzing, and to demonstrate, we get examples on 5G, CoAP and ZigBee probing alike, with a list of found CVEs to wrap the README up. As Wikipedia often states, this list is incomplete, and you can help by expanding it. Fuzzing is an underestimated tool – it will help you hack ubiquitous wireless protocols, proprietary standards, and smart home hubs alike.

Flipper Zero Panic Spreads To Oz: Cars Unaffected

April 1, 2024 by 15 Comments

A feature of coming to adulthood for any young person in the last quarter of the twentieth century would have been the yearly warnings about the danger of adulterated Halloween treats. Stories were breathlessly repeated of apples with razor blades in them, or of chocolate bars laced with rat poison, and though such tales often carried examples of kids who’d died horrible deaths in other far-away places, the whole panic was (as far as we know) a baseless urban legend.

It’s difficult not to be reminded of those times today then, as we read news from Australia warning about the threat from the Flipper Zero wireless hacking tool. It has the same ingredients, of an imaginary threat earnestly repeated by law enforcement officers, and lapped up by a credulous media with little appetite for verifying what they print.

This is a story which first appeared in mid-February in Canada, when a government minister singled out the Flipper Zero as a car theft tool and promised to ban it. This prompted a storm of derision from tech-savvy Canadians and others who immediately pointed out that vehicle security has long ago eclipsed the capabilities of the Flipper, and that there are far more pertinent threats such as those from CAN bus attacks or even RF boosters. Despite this debunking, it seems to have spread. Where will Flipper Mania pop up next?

Canada and Australia are both countries with a free press; that press should be doing their job on these stories by fact-checking and asking pertinent questions when the facts don’t fit the story. When it comes to technology stories it seems not doing this has become the norm.

Thanks [Peter Caldwell] for the tip.

anfractuosity's test setup showing the Pi under test and a few pieces of equipment used to perform the attack

Cold Boot Attack You Can Do With A Pi

April 1, 2024 by 2 Comments

A cold boot attack is a way to extract RAM contents from a running system by power cycling it and reading out RAM immediately after loading your own OS. How easy is it for you to perform such an attack? As [anfractuosity] shows, you can perform a cold boot attack with a Raspberry Pi, with a reasonably simple hardware setup and a hefty chunk of bare-metal code.

[anfractuosity]’s setup is simple enough. The Pi 4 under attack is set up to boot from USB drive, and a relay board has it switch between two possible USB drives to boot from: one with a program that fills RAM with , and another with a program that extracts RAM out through UART. The process is controlled by another Pi controlling the relays through GPIOs, that also monitors the target Pi’s UART and uses it as a channel to extract memory.

The outcomes are pretty impressive. After 0.75s of power-down, most of the image could be extracted. That’s without any cooling, so abusing a can of electronics duster is likely to improve these results dramatically. Want to play with cold boot attacks? [anfractuosity]’s code is great for getting your feet wet. Furthermore, the code examples provided serve as a wonderful playground for general memory attack research.

Raspberry Pi not fun enough for you anymore? Well then, you can always start playing with Android phones!

Exploit The Stressed-out Package Maintainer, Exploit The Software Package

March 31, 2024 by 10 Comments

A recent security vulnerability — a potential ssh backdoor via the liblzma library in the xz package — is having a lot of analysis done on how the vulnerability was introduced, and [Rob Mensching] felt that it was important to highlight what he saw as step number zero of the whole process: exploit the fact that a stressed package maintainer has burned out. Apply pressure from multiple sources while the attacker is the only one stepping forward to help, then inherit the trust built up by the original maintainer. Sadly, [Rob] sees in these interactions a microcosm of what happens far too frequently in open source.

Maintaining open source projects can be a high stress activity. The pressure and expectations to continually provide timely interaction, support, and updates can easily end up being unhealthy. As [Rob] points out (and other developers have observed in different ways), this kind of behavior just seems more or less normal for some projects.

The xz/liblzma vulnerability itself is a developing story, read about it and find links to the relevant analyses in our earlier coverage here.

Security Alert: Potential SSH Backdoor Via Liblzma

March 29, 2024 by 34 Comments

In breaking news that dropped just after our weekly security column went live, a backdoor has been discovered in the xz package, that could potentially compromise SSH logins on Linux systems. The most detailed analysis so far seems to be by [Andres Freund] on the oss-security list.

The xz release tarballs from 5.6.0 in late February and 5.6.1 on March 9th both contain malicious code. A pair of compressed files in the repository contain the majority of the malicious patch, disguised as test files. In practice, this means that looking at the repository doesn’t reveal anything amiss, but downloading the release tarballs gives you the compromised code.

This was discovered because SSH logins on a Debian sid were taking longer, with more CPU cycles than expected. And interestingly, Valgrind was throwing unexpected errors when running on the liblzma library. That last bit was first discovered on February 24th, immediately after the 5.6.0 release. The xz-utils package failed its tests on Gentoo builds.

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