W2KM_BARTALEX.XYUJ

July 30, 2015
 Analysis by: Homer Pacag
 ALIASES:

TrojanDownloader:O97M/Bartallex(Microsoft); Trojan-Downloader.MSWord.Agent.oa (Kaspersky)

 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.

  TECHNICAL DETAILS

File Size:

96,256 bytes

File Type:

DOC

Memory Resident:

No

Initial Samples Received Date:

28 Jul 2015

Arrival Details

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

Installation

This Trojan drops the following files:

  • %User Temp%\{random number}.bat
  • %User Temp%\{random number}.vbs
  • %User Temp%\{random number}.ps1 - for Windows Vista and above only

(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.)

Download Routine

This Trojan accesses the following websites to download files:

  • https://www.{BLOCKED}x.com/s/i4wqt4hzz09qh46/jj_0.exe?dl=1
  • http://{BLOCKED}c.su/5751812.jpg

It saves the files it downloads using the following names:

  • %User Temp%\8.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.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}residency.com/modules/mod_araticlhess/78672738612836.txt
  • http://{BLOCKED}ostainedglassdesignresturation.com/wp-content/themes/ecobiz/ecobiz/css/styles/brown/78672738612836.txt
  • http://{BLOCKED}ostainedglassdesignresturation.com/wp-content/themes/ecobiz/ecobiz/css/styles/brown/fafa.txt