It appears you have been hacked. What firewall are you running? Any? What servers have you setup to run? What ports? You may need to harden your configuration to avoid such incidents in the future.
The command: $ telinit 1
should get you into single user mode.
You can get chkrootkit
here or
here and
rkhunter
here, however as long as you can identify the folder, you should be able to delete it, and then reboot from single user mode by issuing the command:
$ telinit 6
-- Tom