W2KM_DRIDEX.YSOO

 Analysis by: Anthony Joe Melgarejo

 ALIASES:

VBA/TrojanDownloader.Agent.AFL (ESET), Troj/DocDl-AEV (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.

  TECHNICAL DETAILS

File Size:

202,240 bytes

File Type:

DOC

Memory Resident:

Yes

Initial Samples Received Date:

22 Oct 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:

  • %Application Data%\HVtM4jMfSTu.exe

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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}esign.com/images/_notes/p0.jpg

  SOLUTION

Minimum Scan Engine:

9.750

FIRST VSAPI PATTERN FILE:

12.102.06

FIRST VSAPI PATTERN DATE:

22 Oct 2015

VSAPI OPR PATTERN File:

12.103.00

VSAPI OPR PATTERN Date:

23 Oct 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

Restart in Safe Mode

[ Learn More ]

Step 3

Search and delete this file

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There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.  
  • %Application Data%\HVtM4jMfSTu.exe

Step 4

Restart in normal mode and scan your computer with your Trend Micro product for files detected as W2KM_DRIDEX.YSOO. 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 5

Enable the macro virus protection in Microsoft Office Applications

[ Learn More ]


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