badusb

11 Articles

USB HID And Run Exposes Yet Another BadUSB Surface

April 4, 2024 by 19 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.

Showing the dock PCB with a Pi Zero attached and wired up onto it

Is Your USB-C Dock Out To Hack You?

March 26, 2023 by 20 Comments

In today’s installment of Betteridge’s law enforcement, here’s an evil USB-C dock proof-of-concept by [Lachlan Davidson] from [Aura Division]. We’ve seen malicious USB devices aplenty, from cables and chargers to flash drives and even suspicious USB fans. But a dock, however, is new. The gist is simple — you take a stock dock, find a Pi Zero W and wire it up to a USB 2.0 port tapped somewhere inside the dock. Finding a Pi Zero is unquestionably the hardest part in this endeavor — on the software side, everything is ready for you, just flash an SD card with a pre-cooked malicious image and go!

On the surface level, this might seem like a cookie-cutter malicious USB attack. However, there’s a non-technical element to it; USB-C docks are becoming more and more popular, and with the unique level of convenience they provide, the “plug it in” temptation is much higher than with other devices. For instance, in shared workspaces, having a USB-C cable with charging and sometimes even a second monitor is becoming a norm. If you use USB-C day-to-day, the convenience of just plugging a USB-C cable into your laptop becomes too good to pass up on.

This hack doesn’t exactly use any USB-C specific technical features, like Power Delivery (PD) – it’s more about exploiting the convenience factor of USB-C that incentivizes you to plug a USB-C cable in, amplifying an old attack. Now, BadUSB with its keystroke injection is no longer the limit — with a Thunderbolt-capable USB-C dock, you can connect a PCIe device to it internally and even get access to a laptop’s RAM contents. Of course, fearing USB-C cables is not a viable approach, so perhaps it’s time for us to start protecting from BadUSB attacks on the software side.

Build Your Own Two-Factor Authenticator With Good USB

June 18, 2022 by 19 Comments

Two-factor authentication is becoming the norm for many applications and services, and security concerns around phone porting hacks are leading to a phaseout of SMS-based systems. Amidst that backdrop, [Josh] developed his own authentication device by the name of Good USB.

The device can be built using a Arduino Leonardo, SS Micro, or even a BadUSB device. It’s the latter which [Josh] most liked, and since the nefarious device is being repurposed for good, it led to the name Good USB. Basically any Atmega32U4-based device will work, as the key functionality is the ability to emulate a USB keyboard to a host PC.

Using the device is just as simple. With the Good USB plugged in, one simply needs to click a button in the companion app to generate a code for the given account you’re logging in to. Pressing the button on the device then types in the code for you. Alternatively, if your device has no button, it can be set up to simply type the code two seconds after you select an account in the companion app.

The code is on Github for those wishing to make their own. Caveat for the cautious: it’s still a work in progress, and there may be security holes in the current implementation.

If you’re interested in the nuts and bolts of how 2FA works, we’ve looked into that in detail. Video after the break.

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Check Your Halloween Candy For Malicious Payloads

October 28, 2019 by 31 Comments

There’s long been much handwringing around Halloween around the prospect of pins, needles and razor blades being hidden in candy and passed out to children. On the very rare occasion this does happen, the outcome is normally little more than some superficial cuts. However, for 2019, [MG] has developed an altogether different surreptitious payload to be delivered to trick or treaters.

Consisting of a small USB device named DemonSeed, it’s a HID attack gadget in the genre of the BadUSB devices we’ve seen previously. When plugged in, the unit emulates a USB keyboard and can be programmed to enter whatever keystrokes are necessary to take over the machine or exfiltrate data. Files are available on Github for those looking to replicate the device.

The trick here is in the delivery. [MG] has produced a large quantity of these small devices, packaging them in anti-static wrappers. The wrappers contain a note instructing children to insert them into their parent’s work computers to access “game codes”, and to share them with their friends while hiding them from adults.

The idea of children brazenly plugging hostile USB devices into important computers is enough to make any IT manager’s head spin, though we suspect [MG] doesn’t actually intend to deploy these devices in anger. It serves as a great warning about the potential danger of such an attack, however. Stay sharp, and keep your office door locked this October 31st!

WiFi Hides Inside A USB Cable

February 18, 2019 by 42 Comments

If you weren’t scared of USB cables before, you should be now. The O.MG cable (or Offensive MG kit) from [MG] hides a backdoor inside the shell of a USB connector. Plug this cable into your computer and you’ll be the victim of remote attacks over WiFi.

You might be asking what’s inside this tiny USB cable to make it susceptible to such attacks. That’s the trick: inside the shell of the USB ‘A’ connector is a PCB loaded up with a WiFi microcontroller — the documentation doesn’t say which one — that will send payloads over the USB device. Think of it as a BadUSB device, like the USB Rubber Ducky from Hak5, but one that you can remote control. It is the ultimate way into a system, and all anyone has to do is plug a random USB cable into their computer.

In the years BadUSB — an exploit hidden in a device’s USB controller itself — was released upon the world, [MG] has been tirelessly working on making his own malicious USB device, and now it’s finally ready. The O.MG cable hides a backdoor inside the shell of a standard, off-the-shelf USB cable.

The construction of this device is quite impressive, in that it fits entirely inside a USB plug. But this isn’t a just a PCB from a random Chinese board house: [MG] spend 300 hours and $4000 in the last month putting this project together with a Bantam mill and created his own PCBs, with silk screen. That’s impressive no matter how you cut it.

Future updates to this cable that will hack any computer might include a port of ESPloitV2, an Open Source WiFi controlled USB HID keyboard emulator. That will bring a lot of power to this device that’s already extremely capable. In the video attached to this tweet you can see the O.MG cable connected to a MacBook, with [MG] opening up a webpage remotely.

Teardown Of USB Fan Reveals Journalists’ Lack Of Opsec

July 11, 2018 by 109 Comments

Last month, Singapore hosted a summit between the leaders of North Korea and the United States. Accredited journalists invited to the event were given a press kit containing a bottle of water, various paper goods, and a fan that plugs into a USB port.

Understandably, the computer security crowd on Twitter had a great laugh. You shouldn’t plug random USB devices into a computer, especially if you’re a journalist, especially if you’re in a foreign country, and especially if you’re reporting on the highest profile international summit in recent memory. Doing so is just foolhardy.

This is not a story about a USB fan, the teardown thereof, or of spy agencies around the world hacking journalists’ computers. This a story of the need for higher awareness on what we plug into our computers. In this case nothing came of it — the majority of USB devices are merely that and nothing more. One of the fans was recently torn down (PDF) and the data lines are not even connected. (I’ll dive into that later on in this article). But the anecdote provides an opportunity to talk about USB security and how the compulsion to plug every USB device into a computer should be interrupted by a few seconds of thoughtfulness first.

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Malduino Elite – First Impressions

May 31, 2017 by 39 Comments

A while back, I wrote an article about Malduino, an Arduino-based, open-source BadUSB device. I found the project interesting so I signed up for an Elite version and sure enough, the friendly postman dropped it off in my mail box last Friday, which means I got to play around with it over the weekend. For those who missed the article, Malduino is USB device which is able to emulate a keyboard and inject keystrokes, among other things. When in a proper casing, it will just look like a USB flash drive. It’s like those things you see in the movies where a guy plugs in a device and it auto hacks the computer. It ships in two versions, Lite and Elite, both based on the ATmega32U4.

The Lite version is really small, besides the USB connector it only contains a switch, which allows the user to choose between running and programming mode, and a LED, which indicates when the script has finished running.

Original Malduino Elite sketch and Lite prototype

The Elite version is bigger, comes with a Micro-SD card reader and four DIP switches, which allow the user to choose which script to run from the card. It also has the LED, which indicates when a script has finished to run. This allows the user to burn the firmware only once and then program the keystroke injection scripts that stored in the Micro-SD card, in contrast to the Lite version which needs to be flashed each time a user wants to run a different script.

These are the two Malduinos and because they are programmed straight from the Arduino IDE, every feature I just mentioned can be re-programmed, re-purposed or dropped all together. You can buy one and just choose to use it like a ‘normal’ Arduino, although there are not a lot of pins to play around with. This freedom was one the first things I liked about it and actually drove me to participate in the crowd-funding campaign. Read on for the full review.
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