Random root shell on logon screen

Greetings, A Debian wheezy server sometimes shows root shells on the logon window. The system services a number of thin clients with public access. This is a critical security problem. The root shell window is a white rectangle overlaying the actual login pane. Any information would be

Root shell bug on Debian wheezy

Greetings, A root shell sometimes appears during the login sequence on a Debian Wheezy system servicing thin clients. The root shell appears after one enters a login and a password then presses random keys until a box appears with the root prompt and perhaps the rest of the login window. A

root partition 76% after sarge upgrade

Greetings, I recently upgraded a system from woody to sarge and the root partition wound up at 76% full. The woody system was at 15% full. Root is about 100MB in size and /var, /tmp, /usr, /home and swap are in separate partitions. Its a standard scientific desktop (not server)