Although these two articles aren’t CCIE preparation related I think they both are interesting for us Cisco nerds 
Hacker writes rootkit for Cisco’s routers
http://www.networkworld.com/news/2008/051408-hacker-writes-rootkit-for-ciscos.html?page=1
FBI Fears Chinese Hackers Have Back Door Into US Government & Military
http://www.abovetopsecret.com/forum/thread350381/pg1
I apologize for trying to spoil the fun, but so far we haven’t seen anything but marketing. The proper lead-in would be “Hacker claims to have written rootkit for Cisco’s routers”.
Tcl-based IOS backdoors have been known for years and even I’ve written about ways to make a Tcl script into almost a daemon.
Here’s Cisco’s response:
http://tools.cisco.com/security/center/viewAlert.x?alertId=15869