Analysis by: Pearl Charlaine Espejo

ALIASES:

TrojanDownloader:O97M/Bartallex (Microsoft); VBA/TrojanDownloader.Agent.YU (ESET-NOD32); Trojan-Downloader.VBA.Agent (Ikarus); Trojan-Downloader.MSWord.Agent.py (Kaspersky); W97M/Downloader.ajz (McAfee)

 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 on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 121,296 bytes
File Type: DOC
Memory Resident: No
Initial Samples Received Date: 30 Jul 2015

Arrival Details

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}erver.com/components/com_wrapper/78672738612836.txt
  • http://www.{BLOCKED}ebistrita.ro/language/en-GB/78672738612836.txt
  • http://{BLOCKED}server.com/components/com_wrapper/fafa.txt
  • http://www.{BLOCKED}ebistrita.ro/language/en-GB/fafa.txt

However, as of this writing, the said sites are inaccessible.

This is the Trend Micro detection for Microsoft Word documents that are compromised through the insertion of a malicious macro.

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.822.06
FIRST VSAPI PATTERN DATE: 30 Jul 2015
VSAPI OPR PATTERN File: 11.823.00
VSAPI OPR PATTERN Date: 31 Jul 2015

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Scan your computer with your Trend Micro product to delete files detected as W2KM_BARTALEX.XYUO. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.

Step 3

Enable the macro virus protection in Microsoft Office Applications

[ Learn More ]


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