This is an IRC backdoor trojan, and KaZaa spreading worm. When run, the worm copies itself the Windows\System directory and creates 2 registry key values to run at startup:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\
Run\Windows Explorer Update Build 1142=explorer32.exe
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\
RunServices\Windows Explorer Update Build 1142=explorer32.exe
The worm acts as a remote access trojan. It contains an IRC client that connects to a specified IRC channel and waits for commands from an attacker. These commands include instructions for the infected machine to:
Initiate a Denial of Service attack,
Open/close the CD-ROM tray,
Download files,
Update the version of the worm,
Uninstall the worm,
Send system information (CPU, RAM, Disk space, OS version, uptime, etc),
Send IRC messages
The worm also copies itself to the KaZaa shared folder with many different file names to trick users into downloading and running it. Such as (---- denotes masked obscenity):