New Western Union MTCN trojan

MX Lab intercepted a new ZBot trojan today that is being distributed in the famous “Western Union MTCN” format. The message subject is “Western Union Transfer MTCN: 5815328212″. The attached file is a compresses zip archive WesternUnion_SPL90710021.zip containing the malware WesternUnion_SPL90710021.exe. Please note that the numbers in the subject line and/or attachment and executable can change.

The body of the email contains:

Dear customer!

The money transfer you have sent on the 20th of April wasn’t received by the recipient.
According to the Western Union contract the transfers which are not collected in 15 days are to be returned to sender.
To collect funds you need to print the invoice attached to this e-mail and visit the nearest Western Union branch.

Thank you!

When we submitted the virus sample to Virus Total, on 26/05/2009 at 21:27:10 (UTC), we only had 6 of the 40 AV engines detecting the malware. When looking at the details and virus naming we assume that they are being detected by some heuristic features that the AV engines have: Gen:Trojan.Heur.3004FB9EBC (BitDefender, GData), Suspicious file (Panda), (Suspicious) – DNAScan (CAT-QuickHeal). A-Squared and Microsoft have a real virus name: Gen.Trojan!IK and TrojanDownloader:Win32/Bredolab.G.

The trojan will create the following files:

%AppData%\wiaserva.log 
 %Temp%\WER699f.dir00\appcompat.txt 
%Temp%\WER699f.dir00\explorer.exe.hdmp
%Temp%\WER699f.dir00\explorer.exe.mdmp 
%Temp%\WER699f.dir00\manifest.txt 
%System%\wbem\grpconv.exe 

%AppData% is a variable that refers to the file system directory that serves as a common repository for application-specific data. A typical path is C:\Documents and Settings\[UserName]\Application Data.

The following directy is created: %Temp%\WER699f.dir00.
A new process is created in the system: %System%\wbem\grpconv.exe along with some Windows registry modifications.

The following URL is being used: hxxp://dollarpoint.ru/abc/controller.php?action=bot&entity_list=&uid=&first=1&guid=13441600&rnd=8520045

Virus Total permalink and MD5 hash: 53d15dc652a2534572981bab1e2eddf3.

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