Tool Physically Hacks Windows

Posted at Sunday, April 12, 2009

Tool Physically Hacks Windows

Lets an attacker use Firewire to take over a 'locked' Windows machine

No screwdriver required: A researcher has released a plug-and-go physical hacking tool that uses a Firewire cable to “own” a Windows machine within seconds.

Winlockpwn, originally built two years ago, bypasses Windows’s authentication system and lets an attacker take over a “locked” Windows machine without even stealing its password. Adam Boileau, a researcher with Immunity Inc., says he decided it was finally time to make his tool publicly available.

Similar Firewire hacks have been demonstrated on Linux and OS X as well.

With Winlockpwn, the attacker connects a Linux machine to the Firewire port on the victim’s machine. The attacker then gets full read-and-write memory access and the tool deactivates Windows’s password protection that resides in local memory. Then he or she has carte blanche to steal passwords or drop rootkits and keyloggers onto the machine.

“This is just a party-trick demo script thats been lying around my homedir for two years gathering dust,” Boileau blogged this week. “I'm not releasing this because Microsoft didn't respond (they did; it’s not a bug, it's a feature, we all know this). It just seemed topical, with the RAM-freezing thing, and it's a pity to write code and have no one use it.”

Firewire’s abuse should come as no surprise, security experts say. The peripheral bus connection technology lets you read and write to memory, so the weakness is not a true vulnerability, but a feature of the technology.

“That Firewire port is, as designed, literally there to let you plug things into your laptop memory banks,” says Thomas Ptacek, principal with Matasano Security. “When you think of Firewire, you really should just think of a cable coming directly out of your system's DRAM banks. That's basically all Firewire is.”

Ptacek says this tool raises the bar in physical hacking. “People think about physical hacking as something you have to do with a screwdriver and 20 minutes, under cover of darkness. Attacks like Adam's can be done in the time it takes you to pick up a sheet of paper off the office printer,” he says.

Not all machines have Firewire ports, of course, but other researchers have already found ways to get around that, using a PCMCIA Firewire card. And Vista is not immune to such an attack, either: Austrian research firm SEC Consult had previously written a proof of concept for Windows Vista that disables password authentication in the default login routine, so the attacker can log in with an arbitrary password, according to the researchers.

Ptacek says the best defense is to disable Firewire. “I think that enterprises who care about security should make sure they don't issue laptops with enabled Firewire ports,” he says.