There have been a number of proof-of-concept hacks using IEEE1394 devices’ DMA to elevate privileges on a host machine.
The most useful application of this technique is breaking into machines that use full-disk encryption. Now there is a tool that will run from any Unix-Like host (Linux, OSX) and can unlock Windows XP,Vista,7,8,OSX 10.6,10.7,10.8, Ubuntu on both x86 and x64 hosts.
Inception is a FireWire physical memory manipulation and hacking tool exploiting IEEE 1394 SBP-2 DMA. The tool can unlock (any password accepted) and escalate privileges to Administrator/root on almost any machine you have physical access to.
It is primarily intended to do its magic against computers that utilize full disk encryption such as BitLocker, FileVault, TrueCrypt or Pointsec. There are plenty of other (and better) ways to hack a machine that doesn’t pack encryption. Inception is also useful for incident response teams and digital forensics experts when faced with live machines.