Video Cable Becomes Transmitter With TEMPEST-LoRa

July 4, 2025 by 10 Comments

EFI from cables is something every ham loves to hate. What if you modulated, that, though, using an ordinary cable as an antenna? If you used something ubiquitous like a video cable, you might have a very interesting exploit– which is exactly what [Xieyang Sun] and their colleagues have done with TEMPEST-LoRa, a technique to encode LoRa packets into video files.

The concept is pretty simple: a specially-constructed video file contains information to be broadcast via LoRa– the graphics card and the video cable serve as the Tx, and the Rx is any LoRa module. Either VGA or HDMI cables can be used, though the images to create the LoRa signal are obviously going to differ in each case. The only restriction is that the display resolution must be 1080×1920@60Hz, and the video has to play fullscreen. Fullscreen video might make this technique easy to spot if used in an exploit, but on the other hand, the display does not have to be turned on at the time of transmission. If employed by blackhats, one imagines syncing this to power management so the video plays whenever the screen blanks. 

This image sends LoRa. Credit: TEMPEST-LoRa

According to the pre-print, a maximum transmission distance of 81.7m was achieved, and at 21.6 kbps. That’s not blazing fast, sure, but transmission out of a totally air-gapped machine even at dialup speeds is impressive. Code is on the GitHub under an MIT license, though [Xieyang Sun] and the team are white hats, so they point out that it’s provided for academic use. There is a demo video, but as it is on bilbili we don’t have an easy way to embed it. The work has been accepted to the ACM Conference on Computer and Communications Security (2025), so if you’re at the event in Taiwan be sure to check it out. 

We’ve seen similar hacks before, like this one that uses an ethernet cable as an antenna. Getting away from RF, others have used fan noise, or even the once-ubiquitous HDD light. (And here we thought casemakers were just cheaping out when they left those off– no, it’s security!)

Thanks to [Xieyang Sun] for the tip! We’ll be checking the tips line for word from you, just as soon as we finish wrapping ferrites around all our cables.

Hacker Tactic: ESD Diodes

June 19, 2025 by 24 Comments

A hacker’s view on ESD protection can tell you a lot about them. I’ve seen a good few categories of hackers neglecting ESD protection – there’s the yet-inexperienced ones, ones with a devil-may-care attitude, or simply those of us lucky to live in a reasonably humid climate. But until we’re able to control the global weather, your best bet is to befriend some ESD diodes before you get stuck having to replace a microcontroller board firmly soldered into your PCB with help of 40 through-hole pin headers.

Humans are pretty good at generating electric shocks, and oftentimes, you’ll shock your hardware without even feeling the shock yourself. Your GPIOs will feel it, though, and it can propagate beyond just the input/output pins inside your chip. ESD events can be a cause of “weird malfunctions”, sudden hardware latchups, chips dying out of nowhere mid-work – nothing to wish for.

Worry not, though. Want to build hardware that survives? Take a look at ESD diodes, where and how to add them, where to avoid them, and the parameters you want to keep in mind. Oh and, I’ll also talk about all the fancy ways you can mis-use ESD diodes, for good and bad alike!

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ZPUI Could Be Your Tiny Embedded GUI

June 18, 2025 by 17 Comments

One of the most frustrating things to me is looking at a freshly-flashed and just powered up single board computer. My goal with them is always getting to a shell – installing packages, driving GPIOs, testing my proof of concept code, adjusting the device tree to load peripheral drivers. Before I can do any of that, I need shell access, and getting there can be a real hassle.

Time after time, I’ve struggled trying to get to a shell on an SBC. For best results, you’d want to get yourself a keyboard, monitor, and an Ethernet cable. Don’t have those, or there’s no space to place them? Maybe a UART connection will work for you – unless it’s broken or misconfigured. Check your pinouts twice. Sure, nowadays you can put WiFi credentials into a text file in /boot/ – but good luck figuring out the IP address, or debugging any mistakes you might make formatting the file. Nowadays, Pi 4 and 5 expose a USB gadget connection on the USB-C port, and that helps… unless you’re already powering the Pi from that port. There’s really no shortage of failure modes here.

If you put a Pi on your network and it goes offline, you generally just don’t know what happened unless you reboot it, which can make debugging into a living hell. I’ve dealt with single-board computers mounted above fiberglass lifted ceilings, fleets of Pi boards at workshops I organized, pocket-carried Pi boards, and at some point, I got tired of it all. A hacker-aimed computer is meant to be accessible, not painful.

Continue reading “ZPUI Could Be Your Tiny Embedded GUI” →

Rhapsody OS is shown in its boot sequence on a monitor; the edge of the motherboard running it is just visible in the right side of the image.

Bringing An Obscure Apple Operating System To Modern Hardware

June 16, 2025 by 17 Comments

During Apple’s late-90s struggles with profitability, it made a few overtures toward licensing its software to other computer manufacturers, while at the same time trying to modernize its operating system, which was threatening to slip behind Windows. While Apple eventually scrapped their licensing plans, an interesting product of the situation was Rhapsody OS. Although Apple was still building PowerPC computers, Rhapsody also had compatibility with Intel processors, which [Omores] put to good use by running it on a relatively modern i7-3770 CPU.

[Omores] selected a Gigabyte GA-Z68A-D3-B3 motherboard because it supports IDE emulation for SATA drives, a protocol which Rhapsody requires. The operating system installer needs to run from two floppy disks, one for boot and one for drivers. The Gigabyte motherboard doesn’t support a floppy disk drive, so [Omores] used an older Asus P5E motherboard with a floppy drive to install Rhapsody onto an SSD, then transferred the SSD to the Gigabyte board. The installation initially had a kernel panic during installation caused by finding too much memory available. Limiting the physical RAM available to the OS by setting the maxmem value solved this issue.

After this, the graphical installation went fairly smoothly. A serial mouse was essential here, since Rhapsody doesn’t support USB. It detected the video card immediately, and eventually worked with one of [Omores]’s ethernet cards. [Omores] also took a brief look at Rhapsody’s interface. By default, there were no graphical programs for web browsing, decompressing files, or installing programs, so some command line work was necessary to install applications. Of course, the highlight of the video was the installation of a Doom port (RhapsoDoom).

This isn’t the first obscure Apple operating system we’ve seen; some of them have even involved updates to Apple’s original releases. We’ve also seen people build Apple hardware.

Thanks to [Stephen Walters] for the tip!

Network Infrastructure And Demon-Slaying: Virtualization Expands What A Desktop Can Do

June 11, 2025 by 21 Comments

The original DOOM is famously portable — any computer made within at least the last two decades, including those in printers, heart monitors, passenger vehicles, and routers is almost guaranteed to have a port of the iconic 1993 shooter. The more modern iterations in the series are a little trickier to port, though. Multi-core processors, discrete graphics cards, and gigabytes of memory are generally needed, and it’ll be a long time before something like an off-the-shelf router has all of these components.

But with a specialized distribution of Debian Linux called Proxmox and a healthy amount of configuration it’s possible to flip this idea on its head: getting a desktop computer capable of playing modern video games to take over the network infrastructure for a LAN instead, all with minimal impact to the overall desktop experience. In effect, it’s possible to have a router that can not only play DOOM but play 2020’s DOOM Eternal, likely with hardware most of us already have on hand.

The key that makes a setup like this work is virtualization. Although modern software makes it seem otherwise, not every piece of software needs an eight-core processor and 32 GB of memory. With that in mind, virtualization software splits modern multi-core processors into groups which can act as if they are independent computers. These virtual computers or virtual machines (VMs) can directly utilize not only groups or single processor cores independently, but reserved portions of memory as well as other hardware like peripherals and disk drives.

Proxmox itself is a version of Debian with a number of tools available that streamline this process, and it installs on PCs in essentially the same way as any other Linux distribution would. Once installed, tools like LXC for containerization, KVM for full-fledged virtual machines, and an intuitive web interface are easily accessed by the user to allow containers and VMs to be quickly set up, deployed, backed up, removed, and even sent to other Proxmox installations. Continue reading “Network Infrastructure And Demon-Slaying: Virtualization Expands What A Desktop Can Do” →

My Winter Of ’99: The Year Of The Linux Desktop Is Always Next Year

June 3, 2025 by 229 Comments

Growing up as a kid in the 1990s was an almost magical time. We had the best game consoles, increasingly faster computers at a pace not seen before, the rise of the Internet and World Wide Web, as well the best fashion and styles possible between neon and pastel colors, translucent plastic and also this little thing called Windows 95 that’d take the world by storm.

Yet as great as Windows 95 and its successor Windows 98 were, you had to be one of the lucky folks who ended up with a stable Windows 9x installation. The prebuilt (Daewoo) Intel Celeron 400 rig with 64 MB SDRAM that I had splurged on with money earned from summer jobs was not one of those lucky systems, resulting in regular Windows reinstalls.

As a relatively nerdy individual, I was aware of this little community-built operating system called ‘Linux’, with the online forums and the Dutch PC magazine that I read convincing me that it would be a superior alternative to this unstable ‘M$’ Windows 98 SE mess that I was dealing with. Thus it was in the Year of the Linux Desktop (1999) that I went into a computer store and bought a boxed disc set of SuSE 6.3 with included manual.

Fast-forward to 2025, and Windows is installed on all my primary desktop systems, raising the question of what went wrong in ’99. Wasn’t Linux the future of desktop operating systems?

Continue reading “My Winter Of ’99: The Year Of The Linux Desktop Is Always Next Year” →

Hackaday Podcast Ep 322: Fake Hackaday Writers, New Retro Computers, And A Web Rant

May 23, 2025 by 1 Comment

We’re back in Europe for this week’s Hackaday podcast, as Elliot Williams is joined by Jenny List. In the news this week is the passing of Ed Smylie, the engineer who devised the famous improvised carbon dioxide filter that saved the Apollo 13 astronauts with duct tape.

Closer to home is the announcement of the call for participation for this year’s Hackaday Supercon; we know you will have some ideas and projects you’d like to share.

Interesting hacks this week include a new Mac Plus motherboard and Doom (just) running on an Atari ST, while a LoRa secure messenger and an astounding open-source Ethernet switch captivated us on the hardware front. We also take a dive into the Mouse programming language, a minimalist stack-based environment from the 1970s. Among the quick hacks are a semiconductor dopant you can safely make at home, and a beautiful Mac Mini based cyberdeck.

Finally, we wrap up with our colleague [Maya Posch] making the case for a graceful degradation of web standards, something which is now sadly missing from so much of the online world, and then with the discovery that ChatGPT can make a passable show of emulating a Hackaday scribe. Don’t worry folks, we’re still reassuringly meat-based.

Insert MP3 podcast link here.

Continue reading “Hackaday Podcast Ep 322: Fake Hackaday Writers, New Retro Computers, And A Web Rant” →