Allow F-Secure Anti-Virus to disinfect the relevant files.

For more general information on disinfection, please see Removal Instructions.

Detection and Disinfection of Rootkits
If the rootkit is not detected or it is hidden and F-Secure Anti-Virus cannot detect its file, it is still possible to detect the malicious activity by scanning the system with a generic rootkit scanner, such as F-Secure BlackLight.

Backdoor:W32/PcClient.YW attempts to hide processes, files, and registry data. It allows the attacker to perform arbitrary actions on the infected machine.
Backdoor:W32/PcClient.YW also has a rootkit functionality and steals sensitive information from an infected computer.

Installation
Once the Backdoor:W32/PcClient.YW had beenÃÂ?ÂÂ?ÃÂ?  executed, it will drop its components in the following path and filename:

Note: the file size of zhyrikwo.dll might vary due to garbage code appended at the end of the file.
It will also drop the following driver that will communicate with the .dll files in order to hide the malware processes, registry entries and files:

Activity
Part of its payload is that it logs all the keystrokes made by the user and sends this file to a remote hacker.
Another part of the payload is that it has a backdoor component. The backdoor routine is injected into svchost.exe, which is capable of doing the following:

This malware connects to the following site:


Registry
It modifies the following known registry entry as its autostart technique:
Data before:

Data after:

The file zhyrikwo.dll will intercept any access to the original file, sens.dll. as a stealth mechanism, and after executing its malicious routines, will transfer the correct parameters to sens.dll.

It also adds the following autostart registry entry for the driver:

Note: This rootkit can be detected by F-Secure's BlackLight.

Detection

F-Secure Anti-Virus detects this malware with the following updates:

[FSAV_Database_Version]
Version = 2007-03-07_10.