Just a heads-up for anyone still using 5.1.2
I have had 2 reports in the last week of fully patched 5.1.2 servers being compromised and turned into IRC anonomizers using the psyBNC rootkit.
Unfortunately, one of the machines was re-formatted before any forensics could be done. However the other one is still intact & I will hopefully be getting the disk next week.
I will report back here if I can discover exactly how the box was compromised.