W2KM_BARTALEX.XXA

 Analysis by: Anthony Joe Melgarejo

 ALIASES:

TrojanDownloader:O97M/Donoff (Microsoft), W97M/Downloader.ank (McAfee), W97M.Downloader (Symantec), Trojan-Downloader.VBS.Agent.asg (Kaspersky), VBA/TrojanDownloader.Agent.ABY (ESET), Troj/DocDl-ABI (Sophos)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system. As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

24,914 bytes

File Type:

DOCX

Initial Samples Received Date:

17 Sep 2015

Arrival Details

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

Download Routine

This Trojan downloads the file from the following URL and renames the file when stored in the affected system:

  • http://{BLOCKED}.{BLOCKED}.43.146/888.jpg

It saves the files it downloads using the following names:

  • %User Temp%\security295.exe

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

As of this writing, the said sites are inaccessible.