The Sound of (Synthesized) Music

What’s an ADSR envelope generator? If you are a big music hacker, you probably know. If you are like the rest of us, you might need to read [Mich’s] post to find out that it is an attack-decay-sustain-release (ADSR) envelope generator. Still confused? It is a circuit used in music synthesis. You can see a demo of the device in the video below.

Before the Altair–which was sort of the first hobbyist computer you could actually buy–electronics magazines were full of music synthesizer projects that had a lot in common with the analog computers of old. A lot of people took that very seriously and then computers took over the collective consciousness and we found musical hackers started working with (digital) computer-based synthesizers. But the old analog synth designs just won’t die. [Mich’s] ADSR is based on an ancient design, and the amount of information and additions he provides makes it worth a read, even if you don’t fancy building one.

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An Analog Charge Pump Fabrication-Time Attack Compromises A Processor

We will all be used to malicious software, computers and operating systems compromised by viruses, worms, or Trojans. It has become a fact of life, and a whole industry of virus checking software exists to help users defend against it.

Underlying our concerns about malicious software is an assumption that the hardware is inviolate, the computer itself can not be inherently compromised. It’s a false one though, as it is perfectly possible for a processor or other integrated circuit to have a malicious function included in its fabrication. You might think that such functions would not be included by a reputable chip manufacturer, and you’d be right. Unfortunately though because the high cost of chip fabrication means that the semiconductor industry is a web of third-party fabrication houses, there are many opportunities during which extra components can be inserted before the chips are manufactured. University of Michigan researchers have produced a paper on the subject (PDF) detailing a particularly clever attack on a processor that minimizes the number of components required through clever use of a FET gate in a capacitive charge pump.

On-chip backdoors have to be physically stealthy, difficult to trigger accidentally, and easy to trigger by those in the know. Their designers will find a line that changes logic state rarely, and enact a counter on it such that when they trigger it to change state a certain number of times that would never happen accidentally, the exploit is triggered. In the past these counters have been traditional logic circuitry, an effective approach but one that leaves a significant footprint of extra components on the chip for which space must be found, and which can become obvious when the chip is inspected through a microscope.

The University of Michigan backdoor is not a counter but an analog charge pump. Every time its input is toggled, a small amount of charge is stored on the capacitor formed by the gate of a transistor, and eventually its voltage reaches a logic level such that an attack circuit can be triggered. They attached it to the divide-by-zero flag line of an OR1200 open-source processor, from which they could easily trigger it by repeatedly dividing by zero. The beauty of this circuit is both that it uses very few components so can hide more easily, and that the charge leaks away with time so it can not persist in a state likely to be accidentally triggered.

The best hardware hacks are those that are simple, novel, and push a device into doing something it would not otherwise have done. This one has all that, for which we take our hats off to the Michigan team.

If this subject interests you, you might like to take a look at a previous Hackaday Prize finalist: ChipWhisperer.

[Thanks to our colleague Jack via Wired]

Printer Vulnerabilites Almost as Bad as IoT

Recently ZDNet and Gizmodo published articles outlining a critical flaw in a large array of personal printers. While the number of printers with this flaw is staggering, the ramifications are even more impressive. Ultimately, any of these printers could have documents sent to them stolen even if the document was only intended to be printed as a hard copy.

Luckily the people responsible for this discovery are white-hat in nature, and the release of this information has been made public so the responsible parties can fix the security flaws. Whether or not the “responsible party” is the manufacturer of the printer, though, is still somewhat unclear because part of the exploit takes advantage of a standard that is part of almost all consumer-grade printers. The standard itself may need to be patched.

Right now, however, it doesn’t seem clear exactly how deep the rabbit hole goes. We all remember the DDoS attack that was caused by Internet of Things devices that were poorly secured, and it seems feasible that networked printers could take some part in a similar botnet if a dedicated user really needed them. At the very least, however, your printed documents might not be secure at all, and you may be seeing a patch for your printer’s firmware in the near future.


Botnet Recall of Things

After a tough summer of botnet attacks by Internet-of-Things things came to a head last week and took down many popular websites for folks in the eastern US, more attention has finally been paid to what to do about this mess. We’ve wracked our brains, and the best we can come up with is that it’s the manufacturers’ responsibility to secure their devices.

Chinese DVR manufacturer Xiongmai, predictably, thinks that the end-user is to blame, but is also consenting to a recall of up to 300 million 4.3 million of their pre-2015 vintage cameras — the ones with hard-coded factory default passwords. (You can cut/paste the text into a translator and have a few laughs, or just take our word for it. The company’s name gets mis-translated frequently throughout as “male” or “masculine”, if that helps.)

Xiongmai’s claim is that their devices were never meant to be exposed to the real Internet, but rather were designed to be used exclusively behind firewalls. That’s apparently the reason for the firmware-coded administrator passwords. (Sigh!) Anyone actually making their Internet of Things thing reachable from the broader network is, according to Xiongmai, being irresponsible. They then go on to accuse a tech website of slander, and produce a friendly ruling from a local court supporting this claim.

Whatever. We understand that Xiongmai has to protect its business, and doesn’t want to admit liability. And in the end, they’re doing the right thing by recalling their devices with hard-coded passwords, so we’ll cut them some slack. Is the threat of massive economic damage from a recall of insecure hardware going to be the driver for manufacturers to be more security conscious? (We kinda hope so.)

Meanwhile, if you can’t get enough botnets, here is a trio of recent articles (one, two, and three) that are all relevant to this device recall.

Via threatpost.

Glitching USB Firmware for Fun

[Micah Elizabeth Scott], aka [scanlime], has been playing around with USB drawing tablets, and got to the point that she wanted with the firmware — to reverse engineer, see what’s going on, and who knows what else. Wacom didn’t design the devices to be user-updateable, so there aren’t copies of the ROMs floating around the web, and the tablet’s microcontroller seems to be locked down to boot.

With the easy avenues turning up dead ends, that means building some custom hardware to get it done and making a very detailed video documenting the project (embedded below). If you’re interested in chip power glitching attacks, and if you don’t suffer from short attention span, watch it, it’s a phenomenal introduction.

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Extra-Large Denial of Service Attack Uses DVRs, Webcams

Brace yourselves. The rest of the media is going to be calling this an “IoT DDOS” and the hype will spin out of control. Hype aside, the facts on the ground make it look like an extremely large distributed denial-of-service attack (DDOS) was just carried out using mostly household appliances (145,607 of them!) rather than grandma’s old Win XP system running on Pentiums.

Slide from <a href="">this talk</a> by Lisa Plesiutschnig
Replace computers with DVRs. Slide from this talk by Lisa Plesiutschnig

We can argue all day about whether a digital video recorder (DVR) or an IP webcam is an “IoT” device and whether this DDOS attack is the biggest to date or merely among them, but the class of devices exploited certainly are not traditional computers, and this is a big hit. Most of these devices run firmware out of flash, and it’s up to the end user (who is not a sysadmin) to keep it up to date or face the wrath of hackers. And it’s certainly the case that as more Internet-facing devices get deployed, the hacker’s attack surface will grow.

Why did the DDOS network use these particular devices? We’re speculating, but we’d guess it’s a combination of difficult-to-update firmware and user “convenience” features like uPnP. To quote the FBI “The UPnP describes the process when a device remotely connects and communicates on a network automatically without authentication.” You can see how this would be good for both the non-tech-savvy and hostile attackers, right? (Turn off UPnP on your router now.)

We alternate between Jekyll and Hyde on the IoT. On one hand, we love having everything in our own home hooked up to our local WiFi network and running on Python scripts. On the other hand, connecting each and every device up to the broader Internet and keeping it secure would be a system administration headache. Average users want the convenience of the latter without having to pay the setup and know-how costs of the former. Right now, they’re left out in the cold. And their toasters are taking down ISPs.

Keep others from snooping in your digital life

In our digital age prying eyes are everywhere. The sad thing is that they may even belong to your own government. But no matter who it is, there are some things you can do to keep your private digital devices and content as secure as possible.

The link above goes to [Jerry Whiting’s] discussion on the topic. He’s certainly an interesting speaker, but make sure you’re using headphones at work as the language can be a bit sultry once in a while. He aims the lesson at the Occupy movement, but it’s a fun listen for any conspiracy theorist out there. The topics run the gamut, starting with the specter of physical access, then moving on to protecting your network through traffic analysis and using key pairs. This Security 101 segment comes in two parts (the first one is embedded after the break), each a bit more than thirty minutes. He’s planning to post a second lesson covering hashes and encryption. Continue reading “Keep others from snooping in your digital life”