A new worm is spreading fast on the Skype network, it’s activated by a malicious Skype Chat link and it has been seen in the wild in numerous places.

Apparently the dangerous link starts with “Check this!” pointing to a .org/.biz address, if you click the link you’ll become infected.

There have been no reports of unpatched issues with Skype so the vector for the attack at present is unknown, after discussion with the Skype developers it’s found the Trojan is using features from the Skype API to propogate, so there is no flaw in Skype.

The end-user who is running Skype does get notified that a program is attempting to access it and must acknowledge it.

From Websense the details we have are:

• The filename is sp.exe
• Assuming the file is run it appears to drop and run a password stealing Trojan Horse
• The file also appears to run another set of code that uses Skype to propagate the original file
• The file is packed and has anti-debugging routines (NTKrnl Secure Suite packer)
• The file connects to a remote server for additional code
• The original site has been black holed and is not serving the code anymore
• The original infections appear to be in APAC region (Korea in particular)

It appears that Symantec uses name W32.Chatosky when they released a description document about the worm.

The malware queries Skype for random users every three minutes and an error message is being displayed if there is no Skype installed to the system.

As always be wary