Small.CGS

Classification

Small.CGS

Summary

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

Removal

Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

Check for the latest database updates
First check if your F-Secure security program is using the latest updates, then try scanning the file again.
Submit a sample
After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.
Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.
Exclude a file from further scanning
If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.
Note: You need administrative rights to change the settings.

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:

 [HKLM\PATH_TO_FW_POLICY\AuthorizedApplications\List]

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