Backdoor Trojan Win32.Katien was first detected in January of 2004.  The Trojan aspect of the program is a Windows PE EXE file and it is about 50 KB in length.  It is written in Microsoft Visual C++.  It is compressed with UPX.  The backdoor component of the program will kick in and will register itself in the system registries auto-run section: HKLM\Software\Microsoft\Windows\CurrentVersion\Run.  Win32.Katien will attempt to connect to an IRC server in order to await instructions from its author.  This spyware affects all Windows operating systems.

AKA:
Backdoor.Win32.Katien.a,
Backdoor.Katien.a,
DDoS-Kaiten,
IRC Trojan,
DDoS.Kaiten.53507,
Troj/Kaiten,
DDoS:Win32/Kaiten,
TROJ_KATIEN.A,
TR/Katien,
Win32:Kaiten,
BackDoor.Katien.A,
Trojan.Katien.A,
Trj/W32.Katien,
Win32/Katien

Related Files:
systemroot+\system32\iexplore.exe

Recommended Action:
Remove at once.

In order to restore order and security to your system, you can remove Win32.Katien by ceasing all running processes and then removing all related files and folders.  For even more protection, you can opt for a system that will remove ALL spyware and not just one program at a time.  ZookaWare PC Cleaner is an excellent choice for spyware removal.  Recognized with several awards for excellence, ZookaWare PC Cleaner will typically remove all spyware with one scan.