A TEMPEST In A Dongle

November 26, 2017 by 27 Comments

If a couple of generations of spy movies have taught us anything, it’s that secret agents get the best toys. And although it may not be as cool as a radar-equipped Aston Martin or a wire-flying rig for impossible vault heists, this DIY TEMPEST system lets you snoop on computers using secondary RF emissions.

If the term TEMPEST sounds familiar, it’s because we’ve covered it before. [Elliot Williams] gave an introduction to the many modalities that fall under the TEMPEST umbrella, the US National Security Agency’s catch-all codename for bridging air gaps by monitoring the unintended RF, light, or even audio emissions of computers. And more recently, [Brian Benchoff] discussed a TEMPEST hack that avoided the need for thousands of dollars of RF gear, reducing the rig down to an SDR dongle and a simple antenna. There’s even an app for that now: TempestSDR, a multiplatform Java app that lets you screen scrape a monitor based on its RF signature. Trouble is, getting the app running on Windows machines has been a challenge, but RTL-SDR.com reader [flatfishfly] solved some of the major problems and kindly shared the magic. The video below shows TempestSDR results; it’s clear that high-contrast images at easiest to snoop on, but it shows that a $20 dongle and some open-source software can bridge an air gap. Makes you wonder what’s possible with deeper pockets.

RF sniffing is only one of many ways to exfiltrate data from an air-gapped system. From power cords to security cameras, there seems to be no end to the ways to breach systems.

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A Web-Based Modem

October 18, 2017 by 41 Comments

If you are beyond a certain age, you will recall when getting on the Internet was preceded by strange buzzing and squawking noises. Modems used tones to transmit and receive data across ordinary telephone lines. There were lots of tricks used to keep edging the speed of modem up until — at the end — you could download (but not upload) at a blazing 56,000 bits per second. [Martin Kirkholt Melhus] decided to recreate a modem. In a Web browser. No kidding.

We started to say something about a modem in the cloud, but that wouldn’t really be accurate. The modem uses the HTML 5 audio API, so it really runs in the browser. We would have been really surprised if [Martin] had cooked up a modem able to interact with a real modem, but as you might expect, the browser modem only communicates with other instances of itself. If you want a brief introduction to HTML 5 audio, you might enjoy the video below.

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Another Day, Another Air Gap Breached

September 21, 2017 by 48 Comments

What high-tech, ultra-secure data center would be complete without dozens of video cameras directed both inward and outward? After all, the best informatic security means nothing without physical security. But those eyes in the sky can actually serve as a vector for attack, if this air-gap bridging exploit using networked security cameras is any indication.

It seems like the Cyber Security Lab at Ben-Gurion University is the place where air gaps go to die. They’ve knocked off an impressive array of air gap bridging hacks, like modulating power supply fans and hard drive activity indicators. The current work centers on the IR LED arrays commonly seen encircling the lenses of security cameras for night vision illumination. When a networked camera is compromised with their “aIR-Jumper” malware package, data can be exfiltrated from an otherwise secure facility. Using the camera’s API, aIR-Jumper modulates the IR array for low bit-rate data transfer. The receiver can be as simple as a smartphone, which can see the IR light that remains invisible to the naked eye. A compromised camera can even be used to infiltrate data into an air-gapped network, using cameras to watch for modulated signals. They also demonstrated how arrays of cameras can be federated to provide higher data rates and multiple covert channels with ranges of up to several kilometers.

True, the exploit requires physical access to the cameras to install the malware, but given the abysmal state of web camera security, a little social engineering may be the only thing standing between a secure system and a compromised one.

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This WAV File Can Confuse Your Fitbit

March 15, 2017 by 30 Comments

As the devices with which we surround ourselves become ever more connected to the rest of the world, a lot more thought is being given to their security with respect to the internet. It’s important to remember though that this is not the only possible attack vector through which they could be compromised. All devices that incorporate sensors or indicators have the potential to be exploited in some way, whether that is as simple as sniffing the data stream expressed through a flashing LED, or a more complex attack.

Researchers at the University of Michigan and the University of South Carolina have demonstrated a successful attack against MEMS accelerometers such as you might find in a smartphone. They are using carefully crafted sound waves, and can replicate at will any output the device should be capable of returning.

MEMS accelerometers have a microscopic sprung weight with protruding plates that form part of a set of capacitors. The displacement of the weight due to acceleration is measured by looking at the difference between the capacitance on either side of the plates.

The team describe their work in the video we’ve put below the break, though frustratingly they don’t go into quite enough detail other than mentioning anti-aliasing. We suspect that they vibrate the weight such that it matches the sampling frequency of the sensor, and constantly registers a reading at a point on its travel they can dial in through the phase of their applied sound. They demonstrate interference with a model car controlled by a smartphone, and spurious steps added to a Fitbit. The whole thing is enough for the New York Times to worry about hacking a phone with sound waves, which is rather a predictable overreaction that is not shared by the researchers themselves.

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Do You Trust Your Hard Drive Indication Light?

February 25, 2017 by 48 Comments

Researchers in the past have exfiltrated information through air gaps by blinking all sorts of lights from LEDs in keyboards to the main display itself. However, all of these methods all have one problem in common: they are extremely noticeable. If you worked in a high-security lab and your computer screen started to blink at a rapid pace, you might be a little concerned. But fret not, a group of researchers has found a new light to blink (PDF warning). Conveniently, this light blinks “randomly” even without the help of a virus: it’s the hard drive activity indication light.

All jokes aside, this is a massive improvement over previous methods in more ways than one. Since the hard drive light can be activated without kernel access, this exploit can be enacted without root access. Moreover, the group’s experiments show that “sensitive data can be successfully leaked from air-gapped computers via the HDD LED at a maximum bit rate of 4000 bit/s (bits per second), depending on the type of receiver and its distance from the transmitter.” Notably, this speed is “10 times faster than the existing optical covert channels for air-gapped computers.”

We weren’t born last night, and this is not the first time we’ve seen information transmission over air gaps. From cooling fans to practical uses, we’ve seen air gaps overcome. However, there are also plenty of “air gaps” that contain more copper than air, and require correspondingly less effort.

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Hacking On The Weirdest ESP Module

February 13, 2017 by 33 Comments

Sometimes I see a component that’s bizarre enough that I buy it just to see if I can actually do something with it. That’s the case with today’s example, the ESP-14. At first glance, you’d ask yourself what AI Thinker, the maker of many of the more popular ESP8266 modules, was thinking.

The ESP-14 takes the phenomenally powerful ESP8266 chip and buries it underneath one of the cheapest microcontrollers around: the 8-bit STM8S003 “value line” chip. Almost all of the pins of the ESP chip are locked inside the RF cage’s metal tomb — only the power, bootloader, and serial TX/RX pins see the light of day, and the TX/RX pins are shared with the STM8S. The rest of the module’s pins are dedicated to the STM8S. Slaving the ESP8266 to an STM8S is like taking a Ferrari and wrapping it inside a VW Beetle.

I had never touched an STM8 chip before, and just wanted to see what I could do with this strange beast. In the end, ironically, I ended up doing something that wouldn’t be too far out of place on Alibaba, but with a few very Hackaday twists: a monitor for our washer and dryer that reports power usage over MQTT, programmed in Forth with a transparent WiFi serial bridge into the chip for interactive debugging without schlepping down into the basement. Everything’s open, tweakable, and the Forth implementation for the STM8S was even developed here on Hackaday.io.

It’s a weird project for the weirdest of ESP modules. I thought I’d walk you through it and see if it sparks you to come up with any alternative uses for the ESP8266-and-STM8S odd couple that is the ESP-14.

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We’re Fans Of Dave’s Fans

August 13, 2016 by 73 Comments

Hackaday.io contributor extraordinaire [davedarko] gets hot in the summer. We all do. But what separates him from the casual hacker is that he beat the heat by ordering four 120 mm case fans. He then 3D printed a minimalistic tower frame for the fans, and tied them all together with a ULN2004 and an ESP8266. The whole thing is controlled over the network via MQTT. That’s dedication to staying cool.

We really like the aesthetics of this design. A fan made up of fans! But from personal experience, we also know that these large case fans can push a lot of air fairly quietly. That’s important if you’re going to stand something like this up on your desk. While we’re not sure that a desk fan really needs networked individual PWM speed control, we can see the temptation.

Now that they’re individually controlled, nothing stops [davedarko] from turning this into a musical instrument, or even using the fans to transmit data. The only thing we wouldn’t do, despite the temptation to stick our fingers in the blades, is to complicate the design visually. Maybe that would finally teach the cat not to walk around on our desk.