Dissecting a firmware image

dissecting-a-firmware-image

[Leland Flynn] did a great job of picking apart the firmware image for a Westell 9100EM FiOS router. Unfortunately he didn’t actually find the information he was looking for. But he’s not quite done poking around yet either. If you have never tried to make sense of an embedded Linux firmware image this serves as a great beginner’s example of how it’s done.

He was turned on to the project after port scanning his external IP and finding a random login prompt which he certainly didn’t set up. Some searching led him to believe this is some kind of back door for Verizon to push automatic firmware updates to his router. He figured why not see if he could yank the credentials and poke around inside of the machine?

He started by downloading the latest firmware upgrade. Running ‘hexdump’ and ‘strings’ gives him confirmation that the image is based on Linux. He’s then able to pick apart the package, getting at just the filesystem portion. His persistence takes him through extracting and decompressing three different filesystems. Even though he now has access to all of those files, broken symlinks meant a dead-end on his login search.

25th Chaos Communication Congress schedule

The team behind 25C3 has published the first draft of this year’s schedule. The annual Chaos Communication Congress is happening December 27th to 30th in Berlin, Germany. There are plenty of interesting talks already in place. We’re spotting things we want to attend already: The conference starts off with how to solar power your gear, which is followed by open source power line communication. A TOR-based VPN, an open source BIOS, rapid prototyping, holographic techniques, and running your own GSM network are on the bill too.

We’ll have at least three Hack a Day contributors in attendance. Last year featured two of our favorite conference talks: [Drew Endy]’s Biohacking and the MiFare crypto1 RFID crack. We hope to see you there.