You don't even need this. Patrick Stewin and Iurii Bystrov[1] released an excellent paper earlier this year (and Patrick presented his research at 44CON[2] last week) on abusing Intel's iAMT functionality to create an in-firmware keylogger and undetectable (from the host's perspective) exfiltration mechanism for streaming out keystrokes and receiving malware updates.

[1] - http://stewin.org/papers/dimvap15-stewin.pdf

[2] - http://44con.com/talks/#persistent-stealthy-remote-controlle...