A story was released about the New York Times internal network being hacked:

The Register: NY Times Internal Network Hacked

There's one interesting bit in there:

Armed with that information, the hacker could use the intranet account of any employee that hadn't changed their password from the default -- the last four digits of the person's Social Security number. One of those belonged to a worker that had the power to create new accounts, so Lamo set up his own account on the network with higher privileges.
As I say ... the human factor is one of the biggest security risks around!

Cheers,

BrainStop