Wednesday, December 20, 2006

Skype Trojan Horse on the loose, but removal’s easy

Russel Shaw reports:
Yesterday Websense Security Labs reported that there was a potential Worm propagating via Skype (see: After investigation we have discovered that this is not a self propagating worm and is actually a Trojan Horse.

After discussions with the very helpful Skype security team, the behavior of this Trojan using the Skype API is as per the specifications of the API. The end-user who is running Skype does get notified that a program is attempting to access it and must acknowledge it.
*there is no vulnerability in Skype at this time that has been uncovered*
For more details on the Skype API see

At the time of this alert the websites that were used to download the Skype API code and the site that is used to download new copies of the Trojan were both down.
Websense says the original infections appear to be occuring in the Asia Pacific region, especially Korea.

According to Symantec, here's what happens when this piece o' crap launches executes:

1) Searches the registry for the location of the Skype application.

2) Displays the following message and then exits if it cannot find the registry: Error!I could not find Skype !

3) Executes the Skype application and displays the following message if it finds the registry:Warning!Allow this program in skype!

4) Queries Skype for random users every 3 minutes.

5) Starts the Skype application and sends the following message to the users:Check this! [http://][REMOVED]

All that said, this appears to be some pretty weak malware. Symantec says so.
Removal via Symantec's daily virus definition update fixes this…

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