Trust no one: backdoored CPUs

We worried about compromized OSes, BIOSes, read last week about a PNG library bug that lets images run buffer exploits, now CPUs can be backdoored:

From Scheier's Crypto-gram:

Here's an interesting hardware security vulnerability. Turns out that it's possible to update the AMD K8 processor (Athlon64 or Opteron) microcode. And, get this, there's no authentication check. So it's possible that an attacker who has access to a machine can backdoor the CPU. <http://www.realworldtech.com/forums/index.cfm?action=detail&PostNum=252 7&Thread=1&entryID=35446&roomID=11> or http://tinyurl.com/43kod