Tag: soft-shutdown

Featured Updates

BusKill v0.7.0 released
BusKill available in-store (Leipzig ProxySto.re)
BusKill Demos (Windows, MacOS, Linux, TAILS, QubesOS)
Disarm BusKill in QubesOS
BusKill Now Shipping!
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3D-Printable BusKill Prototype Demo

Today we’re ecstatic to publish our first demo showing a homemade BusKill Cable (in the prototype 3D-printed case) triggering a lockscreen.

[BusKill] 3D Printable Dead Man Switch (Demo)

While we do what we can to allow at-risk folks to purchase BusKill cables anonymously, there is always the risk of interdiction.

We don’t consider hologram stickers or tamper-evident tape/crisps/glitter to be sufficient solutions to supply-chain security. Rather, the solution to these attacks is to build open-source, easily inspectable hardware whose integrity can be validated without damaging the device and without sophisticated technology.

Actually, the best way to confirm the integrity of your hardware is to build it yourself. Fortunately, BusKill doesn’t have any circuit boards, microcontrollers, or silicon; it’s trivial to print your own BusKill cable — which is essentially a USB extension cable with a magnetic breakaway in the middle

Mitigating interdiction via 3D printing is one of many reasons that Melanie Allen has been diligently working on prototyping a 3D-printable BusKill cable this year. In this article, we hope to showcase her progress and provide you with some OpenSCAD and .stl files you can use to build your own version of the prototype, if you want to help us test and improve the design.

ⓘ Note: This post is adapted from its original article on Melanie Allen’s blog.

Demo


In our last update, I showed a video demo where I succesfully triggered a lockscreen using a BusKill prototype without the 3D-printed body for the case and N35 disc magnets. I realized that the N35 disc magnets were not strong enough. In this update, I show a demo with the prototype built inside a 3D-printed case and with (stronger) N42 and N52 cube magnets.

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Disarm BusKill in QubesOS

This post will describe how to setup keyboard shortcuts in QubesOS so that you can temporarily disarm (pause) the BusKill laptop kill cord.

This allows the user to, for example, go to the bathroom without causing their computer to shutdown or self-destruct.

This is a guide that builds on part one: A Laptop Kill Cord for QubesOS (1/2). Before reading this, you should already be familiar with how to setup udev rules for BusKill on QubesOS.

  1. A Laptop Kill Cord for QubesOS (1/2)
  2. Disarm BusKill in QubesOS (2/2)

ⓘ Note: This post is adapted from its original article on Tom Hocker’s blog.

What is BusKill?

What if someone literally steals your laptop while you’re working with classified information inside a Whonix DispVM? They’d also be able to recover data from previous DispVMs–as Disposable VM’s rootfs virtual files are not securely shredded after your DispVM is destroyed.

QubesOS Logo
QubesOS: A reasonably secure OS

Are you a security researcher, journalist, or intelligence operative that works in QubesOS–exploiting Qubes’ brilliant security-through-compartimentalization to keep your data safe? Do you make use of Whonix Disposable VMs for your work? Great! This post is for you.

I’m sure your QubesOS laptop has Full Disk Encryption and you’re using a strong passphrase. But what if someone literally steals your laptop while you’re working with classified information inside a Whonix DispVM? Not only will they get access to all of your AppVM’s private data and the currently-running Whonix DispVM’s data, but there’s a high chance they’d be able to recover data from previous DispVMs–as Disposable VM’s rootfs virtual files (volatile.img) are not securely shredded after your DispVM is destroyed by Qubes!

Let’s say you’re a journalist, activist, whistleblower, or a human rights worker in an oppressive regime. Or an intelligence operative behind enemy lines doing research or preparing a top-secret document behind a locked door. What do you do to protect your data, sources, or assets when the secret police suddenly batter down your door? How quickly can you actually act to shutdown your laptop and shred your RAM and/or FDE encryption keys?


BusKill utilizes a magnetic trip-wire that tethers your body to your laptop. If you suddenly jump to your feet or fall off your chair (in response to the battering ram crashing through your door) or your laptop is ripped off your table by a group of armed thugs, the data bus’ magnetic connection will be severed. This event causes a configurable trigger to execute.

The BusKill trigger can be anything from:

  1. locking your screen or
  2. shutting down the computer or
  3. initiating a self-destruct sequence

While our last post described how to setup such a system in QubesOS with BusKill, this post will describe how to add keyboard shortcuts to arm & disarm the dead man switch (eg so you can go to the bathroom).

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BusKill Now Shipping!

We’re excited to announce that our first production run of BusKill cables is now in-stock in our distribution center. Existing orders are going out now, and new orders will ship immediately.

[BusKill] Our Dead Man Switch Magnetic Breakaway cables are Now Shipping!

The first BusKill prototype was born in 2017. It gained international popularity in 2020 when Michael Altfield described how to build your own BusKill cable. After extensive effort and with the help of several contributors, a Linux hacker’s DIY cable got a user-friendly, cross-platform GUI.

When the only USB-A magnetic breakaway coupler on the market became out of stock and EOL’d, we raised $18,507 on CrowdSupply in early 2022 to manufacture our own injection-molded cable. One thousand logistics challenges later, Mouser started shipping BusKill cables to our backers in October 2022.

The assembled BusKill cable is plugged-into the USB-A port of a laptop

Now that the hardware is out the door, we’re hard at work on new features for the BusKill app. Our top goal is to add a soft-shutdown trigger to the existing lock-screen trigger. At the time of writing, this is functional on Linux and Windows. We’re just working out the kinks of privilege escalation on MacOS.

To be notified when we’ve added the soft-shutdown trigger to the BusKill app, you can signup for our newsletter.


We did our best to test BusKill across the three target platforms, but the wide spread of OS versions does leave room for error. If you happen to find a bug with BusKill, please let us know.

If you don’t have a BusKill cable yet, you can buy one here on this website or build your own. And for the makers out there, checkout the progress on our 3D printable BusKill magnetic breakaway coupler 🙂

You can also buy a BusKill cable with bitcoin, monero, and other altcoins directly from our BusKill Store

Bitcoin Accepted Here

Monero Accepted Here

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