This new Instant Messenger (IM) threat should be closely watched as it contains a security backdoor and other sophisticated capabilities.

http://secunia.com/virus_information/22890/virkel.a/

Virkel is a backdoor with IM (Instant Messenger) spreading capabilities. It was first found on October 26th, 2005. The backdoor can provide a hacker with information about a system, work as a proxy, update itself, perform a Denial of Service (DoS) attack, open remote shell, download files. It also kills processes of anti-virus and security software and blocks access to many different sites that belong to anti-virus and security software vendors.