Threat Description



Category: Trojan
Platform: W32
Aliases: Small.CGS


We got reports of this trojan downloader on Jan 27th 2006. The trojan downloader was spammed to a large amount of e-mail addresses. The downloader is programmed to download a backdoor from website.


Automatic action

Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.

More scanning & removal options

More information on scanning or removal options is available in the documentation for your F-Secure security product on the Downloads section of our Home - Global site.

You may also refer to the Knowledge Base on the F-Secure Community site for more information.

Contact Support

For further assistance, F-Secure customers can request support online via the Request support or the Chat forms on our Home - Global site.

Technical Details

The trojan's file is a PE executable file packed with FSG file compressor. According to reports, the trojan was spammed in messages that looked like this:

Subject: YOUR BILL PAYMENT NOT APPROVED!Attachment: BILL_235563880.EXE  

When the attachment is run, the trojan first tries to add its file to Windows XP built-in firewall policy using the following key:


After that, the trojan tries to download and activate backdoor from web site . The backdoor is already detected as Trojan.Win32.Delf.qx with FSAV updates version 2005-12-23_1.


Small.CGS is detected with the following F-Secure Anti-Virus updates:

Detection Type: PC
Database: 2006-01-27_01

Description Details: Jarkko Turkulainen, January 27, 2006
Technical Details:Jarkko Turkulainen, January 27, 2006


Suspect a file or URL was wrongly detected? Submit a sample to our Labs for analysis

Submit Now

Give And Get Advice

Give advice. Get advice. Share the knowledge on our free discussion forum.

Learn More