Unintentional Emissions

First, it was the WiFi router: my ancient WRT54G that had given me nearly two decades service. Something finally gave out in the 2.4 GHz circuitry, and it would WiFi no more. Before my tears could dry, our thermometer went on the fritz. It’s one of those outdoor jobbies that transmits the temperature to an indoor receiver. After that, the remote for our office lights stopped working, but it was long overdue for a battery change.

Meanwhile, my wife had ordered a new outdoor thermometer, and it too was having trouble keeping a link. Quality control these days! Then, my DIY coffee roaster fired up once without any provocation. This thing has worked quasi-reliably for ten years, and I know the hardware and firmware as if I had built them myself – there was no way one of my own tremendously sophisticated creations would be faulty. (That’s a joke, folks.) And then the last straw: the batteries in the office light remote tested good.

We definitely had a poltergeist, a radio poltergeist. And the root cause would turn out to be one of those old chestnuts from the early days of CMOS ICs – never leave an input floating that should have a defined logic level. Let me explain.

The WRT54G was the hub of my own home automation system, an accretion of ESP8266 and other devices that all happily speak MQTT to each other. When it went down, none of the little WiFi nodes could boot up right. One of them, described by yours truly in this video, is an ESP8266 connected to a 433 MHz radio transmitter. Now it gets interesting – the thermometers and the coffee roaster and the office lights all run on 433 MHz.

Here’s how it went down. The WiFi-to-433 bridge failed to connect to the WiFi and errored out before the part of the code where it initialized GPIO pins. The 433 MHz transmitter was powered, but its digital input was left flopping in the breeze, causing it to spit out random data all the time, with a pretty decent antenna. This jammed everything in the house, and apparently even once came up with the command to turn on the coffee roaster, entirely by chance. Anyway, unplugging the bridge fixed everything.

This was a fun one to troubleshoot, if only because it crossed so many different devices at different times, some homebrew and some commercial, and all on different control systems. Until I put it together that everything on 433 MHz was failing, I hadn’t even thought of it as one event. And then it turns out to be a digital electronics classic – the dangling input!

Anyway, hope you enjoyed the ride. And spill some copper for the humble pull-down resistor.

Matthew [wrongbaud] Alt Is Fighting The Good Fight

In a perfect world, all of our electronic devices would come with complete documentation, and there’d be open source libraries available for interfacing them with whatever we wanted. There’d never be arbitrary lockouts preventing us from using a piece of hardware in a way the manufacturer didn’t approve of, and the “cloud” wouldn’t be a black-box server in some data center on the other side of the planet, but a transparent and flexible infrastructure for securely storing and sharing information.

Unfortunately, that’s not the world we live in. What’s worse, rather than moving towards that electronic utopia, the industry appears to be heading in the opposite direction. It seems like every month we hear about another service shutting down and leaving viable hardware to twist in the wind. Just yesterday Google announced they’d be retiring their Stadia game streaming service early next year — leaving users with unique Internet-connected controllers that will no longer have a back-end to communicate with.

Matthew Alt

Luckily for us, there’s folks like Matthew [wrongbaud] Alt out there. This prolific hacker specializes in reverse engineering, and has a knack not just for figuring out how things work, but in communicating those findings with others. His conquests have graced these pages many times, and we were fortunate enough to have him helm the Introduction to Reverse Engineering with Ghidra class for HackadayU back in 2020. This week, he stopped by the Hack Chat to talk about the past, present, and future of reverse engineering.

Matthew got his start in reverse engineering during college, when he was working in a shop that specialized in tuning engine control units (ECUs). He was responsible for figuring out how the ECUs functioned, which ultimately would allow them to be modified to improve engine performance beyond the vehicle’s stock configuration. Sometimes that involved uploading modified calibration data, or disabling functions that were detrimental to engine performance. These software changes could potentially increase engine output by as much as 50 HP, though he says that sometimes the goal was to simply increase throttle response so the vehicle would feel more aggressive on the road.

Moving on to the tools of the trade, Matthew explained why he prefers using Ghidra for embedded targets over classic reverse engineering tools like IDA Pro. As an example he points to a recent project where he used Ghidra’s API and intermediary language PCode to crack passwords in Game Boy Advance games. Though he does mention that IDA still has its place if you’re looking to peek into some Windows C++ software.

Matthew also pointed to new techniques and tools for working with fault injection which have opened up a lot of exciting possibilities over the last few years. In fact, he says tools like ChipWhisperer will become invaluable as newer devices adopt advanced security features. When gadgets are using secure boot and encrypted firmware, gaining access is going to take a bit more than just finding an unleaded serial port on the board. Glitching attacks will become more commonplace, so you might as well get up to speed now.

Colin O’Flynn’s ChipWhisperer makes side-channel power analysis and glitching attacks far more accessible.

To that end, Matthew pointed out a number of instructional courses that he and other hardware hackers such as Joe Grand have put together for those who want to get started with practical reverse engineering and have some disposable income. For those who’d rather work though it on their own, he dropped links to several Capture-the-Flag (CTF) events and wargames you can use to hone your skills.

We’d like to thank Matthew Alt for not just stopping by the Hack Chat, but for being such a good friend to the Hackaday community. His work has been inspirational for all of us here, and it’s always exciting when he’s penned a new blog post detailing another challenge bested. The next time your favorite MegaCorp releases some anti-consumer gadget, you can take some comfort in knowing he’s still out there bending hardware to his will.


The Hack Chat is a weekly online chat session hosted by leading experts from all corners of the hardware hacking universe. It’s a great way for hackers connect in a fun and informal way, but if you can’t make it live, these overview posts as well as the transcripts posted to Hackaday.io make sure you don’t miss out.

Hackaday Podcast 187: The Sound Of Gleeful Gerbils, The Song Of The Hard Drive, And A Lipstick Pickup Lullaby

This week, Editor-in-Chief Elliot Williams and Assignments Editor Kristina Panos gushed about NASA’s live obliteration of minor planet Dimorphos using a probe outfitted with a camera. Spoiler alert: the probe reaches its rock-dappled rocky target just fine, and the final transmitted image has a decidedly human tinge.

Kristina brought the mystery sound again this week, much to Elliot’s sonic delight. Did he get it? Did he figure it out? Well, no. The important thing is one of you is bound to get it.

We kick off the hacks with a really neat 3D printed linkage that acts as an elevator for a marble run, and then we discuss a mid-century hack that helps you decide whether it’s time to emerge from the fallout shelter using the contents of your typical 1950s pockets. We spent a few minutes comparing our recent radiation exposure levels  — Kristina wins with about a dozen x-rays so far this year, but no full-body CT scans. Then we talk guitars for a bit, remember a forgotten CPU from TI, and spend a few cycles talking about a tone-wheel organ that sounds like a chorus of gleeful gerbils.

Finally, we talk toner transfer for 3D prints, argue in defense of small teams versus large committees, and get all tangled up in cursive.

Direct download.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

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This Week In Security: Exchange 0-day, Doppelgangers, And Python Gets Bit In The TAR

According to researchers at GTSC, there’s an unpatched 0-day being used in-the-wild to exploit fully patched Microsoft Exchange servers. When they found one compromised server, they made the report to Microsoft through ZDI, but upon finding multiple Exchange servers compromised, they’re sounding the alarm for everyone. It looks like it’s an attack similar to ProxyShell, in that it uses the auto-discover endpoint as a starting point. They suspect it’s a Chinese group that’s using the exploit, based on some of the indicators found in the webshell that gets installed.

There is a temporary mitigation, adding a URL-based request block on the string .*autodiscover\.json.*\@.*Powershell.. The exact details are available in the post. If you’re running Exchange with IIS, this should probably get added to your system right now. Next, use either the automated tool, or run the PowerShell one-liner to detect compromise: Get-ChildItem -Recurse -Path -Filter "*.log" | Select-String -Pattern 'powershell.*autodiscover\.json.*\@.*200. This one has the potential to be another really nasty problem, and may be wormable. As of the time of writing, this is an outstanding, unpatched problem in Microsoft Exchange. Come back and finish the rest of this article after you’ve safed up your systems.

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Intranasal Vaccines: A Potential Off-Ramp For Coronavirus Pandemics

An interesting and also annoying aspect about the human immune system is that it is not a neat, centralized system where you input an antigen pattern in one spot and suddenly every T and B lymphocyte in the body knows how to target an intruder. Generally, immunity stays confined to specific areas, such as the vascular and lymph system, as well as the intestinal and mucosal (nasal) parts of the body.

The result of this is that specific types of vaccines have a different effect, as is demonstrated quite succinctly with the polio vaccines. The main difference between the oral polio vaccine (OPV) and inactivated vaccine (injected polio vaccine, or IPV) is that the former uses a weakened virus that induces strong immunity in the intestines, something that the latter does not. The effect of this is that while both protect the individual, it does not affect the fecal-oral infection route of the polio virus and thus the community spread.

The best outcome for a vaccine is when it both protects the individual, while also preventing further infections as part of so-called sterilizing immunity. This latter property is what makes the OPV vaccine so attractive, as it prevents community spread, while IPV is sufficient later on, as part of routine vaccinations. The decision to use a vaccine like the OPV versus the IPV is one of the ways doctors can tune a population’s protection against a disease.

This is where the current batch of commonly used SARS-CoV-2 vaccines are showing a major issue, as they do not provide significant immunity in the nasal passage’s mucosal tissues, even though this is where the virus initially infects a host, as well as where it replicates and infects others from. Here intranasal vaccines may achieve what OPV did for polio.

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2022 Hackaday Prize: Congratulations To The Winners Of The Climate-Resilient Communities Challenge

Holy humanitarian hacking, Batman! We asked you to come up with your best climate-forward ideas, and you knocked it out of the ionosphere! Once again, the judges had a hard time narrowing down the field to just ten winners, but they ultimately pulled it off — and here are the prize-winning projects without much further ado.

In the Climate-Resilient Challenge, we asked you to design devices that help build communities’ resilience to severe weather and the increasing frequency of natural disasters due to climate change, and/or devices that collect environmental data that serves as hard evidence in the fight for changes in local infrastructure. While several people focused on air quality, which is something we tend to think of as a human need, plenty others thought of the flora and fauna with which we share this planet.

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Japan Wants To Decarbonize With The Help Of Ammonia

With climate change concerns front of mind, the world is desperate to get to net-zero carbon output as soon as possible. While direct electrification is becoming popular for regular passenger cars, it’s not yet practical for more energy-intensive applications like aircraft or intercontinental shipping. Thus, the hunt has been on for cleaner replacements for conventional fossil fuels.

Hydrogen is the most commonly cited, desirable for the fact that it burns very cleanly. Its only main combustion product is water, though its combustion can generate some nitrogen oxides when burned with air. However, hydrogen is yet to catch on en-masse, due largely to issues around transport, storage, and production.

This could all change, however, with the help of one garden-variety chemical: ammonia. Ammonia is now coming to the fore as an alternative solution. It’s often been cited as a potential way to store and transport hydrogen in an alternative chemical form, since its formula consists of one nitrogen atom and three hydrogen atoms.However, more recently, ammonia is being considered as a fuel in its own right.

Let’s take a look at how this common cleaning product could be part of a new energy revolution.

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