Analysis by: Mark Joseph Manahan


Exp/20120158-A (Sophos) , MSOffice/CVE20120158.fam!exploit (Fortinet) ,Exploit:Win32/Shellcode.AB (Microsoft) ,Exploit.MSWord.CVE-2012-0158.ab (v) (Sunbelt)


Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)


  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes


Infection Channel: Spammed via email

This malicious .DOC file entitled "Violent terror attack" took advantage of the mass stabbing incident in Kunming, China in early March 2014, as social engineering bait. It exploited Microsoft Office vulnerability CVE-2012-0158 to drop a backdoor, BKDR_GHOST.LRK.

To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.

This Trojan arrives as attachment to mass-mailed email messages.

It executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

It takes advantage of certain vulnerabilities.


File Size: 215,360 bytes
File Type: MSG, DOC
Memory Resident: No
Initial Samples Received Date: 04 Mar 2014
Payload: Drops files

Arrival Details

This Trojan arrives as attachment to mass-mailed email messages.

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\aa.doc - decoy document file
  • %User Temp%\DW20.exe - detected as BKDR_GHOST.LRK

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.)

It executes the dropped file. As a result, malicious routines of the dropped file are exhibited on the affected system.

Other Details

This Trojan takes advantage of the following vulnerabilities:


Minimum Scan Engine: 9.700
VSAPI OPR PATTERN File: 10.643.00
VSAPI OPR PATTERN Date: 04 Mar 2014

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 2

Remove the malware/grayware file dropped/downloaded by TROJ_EXPLOYT.AGH. (Note: Please skip this step if the threat(s) listed below have already been removed.)

Step 3

Search and delete these files

[ Learn More ]
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.
  • %User Temp%\aa.doc

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_EXPLOYT.AGH 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 the following Trend Micro Support pages for more information:

Step 5

Download and apply this security patch Refrain from using these products until the appropriate patches have been installed. Trend Micro advises users to download critical patches upon release by vendors.

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