A mediagenic press-release from Proofpoint, a security firm, announced that its researchers had discovered a 100,000-device-strong botnet made up of hacked "Internet of Things" appliances, such as refrigerators. The story's very interesting, but also wildly implausible as Ars Technica's Dan Goodin explains.
The report is light on technical details, and the details that the company supplied to Goodin later just don't add up. Nevertheless, the idea of embedded systems being recruited to botnets isn't inherently implausible, and some of the attacks that Ang Cui has demonstrated scare the heck out of me.
For more speculation, see my story The Brave Little Toaster, from MIT's TRSF.
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A Symantec researcher has discovered a worm that runs on embedded Linux systems, like those found in set-top boxes and routers. It's common for owners of these devices to forget about them, letting them run in the background for so long as they don't misbehave -- and as a result, they are often out of date. The worm, called Linux.Darlloz, attacks out-of-date Linux installations running on Intel hardware (a small minority in the embedded systems world), but it would not be hard to modify it to attack embedded linuces on other chips.
In addition to being out-of-date, many of these systems have "forever day" bugs that will never be patched by their vendors, making them especially hard to secure. The anonymously authored "Internet Census 2012: Port scanning /0 using insecure embedded devices" showed that a dedicated attacker could compromise well over a million devices without much work, recruiting them to run unprecedented denial of service attacks (I wonder if anyone's thought of using this method for mining Bitcoins?).
As the researcher Ang Cui has demonstrated, embedded systems attacks are especially pernicious because it's difficult to boot them from known-good sources. Once an attacker compromises your router, printer, or set-top box, she can reprogram it to give the appearance of accepting updates without actually installing them, meaning that the system can never be provably restored to your control.
The details of the Linux.Darlloz show a much more primitive and unambitious attack, but it hints at a pretty frightening future for the compromised Internet-of-Things (I wrote a short story about this, called "The Brave Little Toaster"). Read the rest
Here's a video of Ang Cui and Michael Costello's Hacking Cisco Phones talk at the 29th Chaos Communications Congress in Berlin.
One of the most mind-blowing presentations at this year's Chaos Communications Congress (28C3) was Ang Cui's Print Me If You Dare, in which he explained how he reverse-engineered the firmware-update process for HPs hundreds of millions of printers. Cui discovered that he could load arbitrary software into any printer by embedding it in a malicious document or by connecting to the printer online. As part of his presentation, he performed two demonstrations: in the first, he sent a document to a printer that contained a malicious version of the OS that caused it to copy the documents it printed and post them to an IP address on the Internet; in the second, he took over a remote printer with a malicious document, caused that printer to scan the LAN for vulnerable PCs, compromise a PC, and turn it into a proxy that gave him access through the firewall (I got shivers).
Cui gave HP a month to issue patches for the vulnerabilities he discovered, and HP now has new firmware available that fixes this (his initial disclosure was misreported in the press as making printers vulnerable to being overheated and turning into "flaming death bombs" -- he showed a lightly singed sheet of paper that represented the closest he could come to this claim). He urges anyone with an HP printer to apply the latest patch, because malware could be crafted to take over your printer and then falsely report that it has accepted the patch while discarding it.
Cui's tale of reverse-engineering is a fantastic look at the craft and practice of exploring security vulnerabilities. Read the rest