Self-Destructing USB Drive Releases The Magic Smoke

March 1, 2023 by Tom Nardi 51 Comments

There were some that doubted the day would ever come, but we’re happy to report that the ambitious self-destructing USB drive that security researcher [Walker] has been working on for the last 6+ months has finally stopped working. Which in this case, is a good thing.

Readers may recall that the goal of the Ovrdrive project was to create a standard-looking flash drive that didn’t just hide or erase its contents when accessed by an unauthorized user, but actively damaged itself to try and prevent any forensic recovery of the data in question. To achieve this, [Walker] built a voltage doubler circuit into the drive that produces 10 volts from the nominal 5 VDC coming from the USB port. At the command of an onboard microcontroller, that 10 V is connected to the circuit’s 3.3 V rail to set off the fireworks.

Early attempts only corrupted some of the data, so [Walker] added some more capacitance to the circuit to build up more of a charge. With the revised circuit the USB controller IC visibly popped, but even after it was replaced, the NAND flash was still unresponsive. Sounds pretty dead to us.

Unfortunately, there’s still at least one issue that’s holding back the design. As we mentioned previously, [Walker] was having trouble getting the computer to actually acknowledge his homebrew drive had any free space available. It turns out that the SM3257EN USB controller IC he’s using needs to be initialized by some poorly documented Windows XP software, which might not be such a big deal if the goal was just to build one of them, but could obviously be a hindrance when going into production.

He hopes further reverse engineering will allow him to determine which commands the XP software is giving to the IC so that he can duplicate them in a less ancient environment. Sounds like a job for Wireshark to us — with any luck he should be able to capture the commands being sent to the hardware and replay them.

While we can understand some readers may have lingering doubts about the drive’s spit-detection authentication system, it’s clear [Walker] has made some incredible progress here. This project demonstrates that not only can an individual spin up their own sold state storage, but that should they ever need to, they can also destroy it in an instant.

The Spit-Detecting USB Flash Drive Is Nearly Here

December 25, 2022 by Tom Nardi 17 Comments

Regular readers may recall that security researcher and general open source hardware fanatic [Walker] has been planning a rather unusual flash drive for some time — one that will only show its contents if the user makes sure to lick their fingers before plugging it in. We’re pleased to report that theory has recently given way to real hardware, and the Ovrdrive “self-destructing” flash drive is now a step closer to reality.

The last time we checked in with [Walker], he hadn’t yet put any hardware together, though he was fairly sure what components he would need and how it would all go together. This was assisted somewhat by the fact that USB flash drives are such a ubiquitous piece of tech, making their principle parts plentiful and fairly well documented. As explained in the video below, all you really need to spin up your own flash drive is the USB connector, the controller chip, and a nice slab of flash memory for it to access. Though naturally you’re on your own for spit detection.

The build video has some gorgeous camera work.

What we especially like about this project is that [Walker] is releasing the whole thing as open source hardware. So even if you’re not interested in the whole lick-for-access feature, you’ve still got a boilerplate flash drive design to build on. We haven’t seen a lot of DIY projects tackle USB Mass Storage previously, and perhaps this design can change that.

But of course, only if the thing works. According to the video after the break, [Walker] seems to have hit a snag with this revision of the hardware. While it enumerates as a storage device when plugged into the computer, the operating system claims its capacity is zero. He thinks there might be a swapped trace between the controller and flash chip to blame, so hopefully he can get things sorted out before too long. We’ve been covering this project since the summer, and are eager to see it cross the finish line.

Continue reading “The Spit-Detecting USB Flash Drive Is Nearly Here” →

So How Do You Make A Self-Destructing Flash Drive?

September 26, 2022 by Tom Nardi 57 Comments

A self-destructing storage device that vaporizes its contents at the first sign of trouble would be an invaluable tool for many people, but good luck getting your hands on such a thing if you don’t work for a three-letter agency. Or at least, that’s what we would have said before [Walker] got on the case. He’s working on an open source self-destructing USB flash drive for journalists, security researchers, whistleblowers, or anyone else who really values their privacy.

When we previously covered this project in July, [Walker] had only planned to make the flash drive hide its contents unless you knew to wet your fingers before plugging it in. We admit it sounds a little weird, but as far as clandestine methods of activating something goes, it’s pretty clever. But based on the feedback he received, he decided to go all-in and make the USB drive literally trash itself should it be accessed by somebody who doesn’t know the secret.

An elegant weapon for a more civilized age.

But how exactly do you pull that off? Sure we’d love to see a small thermite charge or vial of acid packed in there, but obviously that’s not very practical. It needs to be safe to carry around, and just as importantly, unlikely to get you into even more trouble with whoever is searching through your belongings. To that end, [Walker] thinks he’s come up with an elegant solution.

The datasheet for his flash memory chip says the maximum voltage it can handle before releasing the Magic Smoke is a meager 4.6 V. So he figures running a voltage doubler on the nominal 5 V coming from a USB port should disable the chip nicely with a minimum of external drama. Will it be enough to prevent the data from being recovered forensically? We don’t know, but we’re eager to find out.

In the write-up, [Walker] takes readers through the circuit designs he’s come up so far, and shows off the source code that will run on the ATtiny25 to determine when it’s time to toast the flash. He says by the next post he should have the entire flash drive built and documented, so stay tuned.

Killer USB Drive Is Designed To Fry Laptops

March 11, 2015 by Ethan Zonca 183 Comments

[Dark Purple] recently heard a story about how someone stole a flash drive from a passenger on the subway. The thief plugged the flash drive into his computer and discovered that instead of containing any valuable data, it completely fried his computer. The fake flash drive apparently contained circuitry designed to break whatever computer it was plugged into. Since the concept sounded pretty amazing, [Dark Purple] set out to make his own computer-frying USB drive.

While any electrical port on a computer is a great entry point for potentially hazardous signals, USB is pretty well protected. If you short power and ground together, the port simply shuts off. Pass through a few kV of static electricity and TVS diodes safely shunt the power. Feed in an RF signal and the inline filtering beads dissipate most of the energy.

To get around or break through these protections, [Dark Purple]’s design uses an inverting DC-DC converter. The converter takes power from the USB port to charge a capacitor bank up to -110VDC. After the caps are charged, the converter shuts down and a transistor shunts the capacitor voltage to the data pins of the port. Once the caps are discharged, the supply fires back up and the cycle repeats until the computer is fried (typically as long as bus voltage is present). The combination of high voltage and high current is enough to defeat the small TVS diodes on the bus lines and successfully fry some sensitive components—and often the CPU. USB is typically integrated with the CPU in most modern laptops, which makes this attack very effective.

Thanks for the tip, [Pinner].

Repairing Dead USB Flash Drives

November 27, 2013 by Brian Benchoff 28 Comments

Over the last few years, [Tobias] has repaired a number of USB Flash drives. This strikes us as a little odd, given small capacity Flash drives are effectively free in the form of conference handouts and swag, but we’re guessing [Tobias] has had a few too many friends lose their thesis to a broken Flash drive.

In all his repairs, [Tobias] found one thing in common The crystal responsible for communicating with the USB controller is always broken. In a way, this makes a lot of sense; everything else on a Flash drive is silicon encased in an epoxy package, where the crystal is a somewhat fragile piece of quartz. Breaking even a small part of this crystal will drastically change the frequency it resonates at making the USB controller throw a fit.

[Tobias]’ solution for all his Flash drive repairs is to desolder and change out the crystal, bringing the drive back to life. Some of the USB Flash drives even have multiple pads for different crystal packages, making it easy to kludge together a solution should you need to repair a Flash drive five minutes ago.

This Is A Peer-to-peer Filesharing Network

October 30, 2010 by Mike Szczys 116 Comments

[Aram Bartholl] is building his own filesharing network that screws those fat cats who want to control your freedom. He’s added file cache devices throughout NYC (five so far but more to come) that are anonymous and free to use. Upload what you want, download what you want. They’re completely offline which means monitoring who’s doing what gets a lot harder and quite possibly requires a warrant from a Judge (we’re obviously not legal experts, your mileage may vary).

As for the slew of comments that are sure to point out the dangers of malicious USB device; We think everyone knows they’re taking on some risk when connecting to a USB plug protruding from a brick wall.

[Thanks Neckbeard]