Analysis by: MarfelTi
 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan takes advantage of software vulnerabilities in certain software to drop malicious files.

  TECHNICAL DETAILS

File Size: 90,667 bytes
File Type: RTF
Memory Resident: No
Initial Samples Received Date: 04 May 2011

Installation

This Trojan drops the following non-malicious files:

  • %User Temp%\{malware filename}.doc

(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.)

Dropping Routine

This Trojan takes advantage of unknown vulnerabilities in the following software to drop malicious files:

NOTES:

Once a malware successfully exploits the said vulnerability, it drops the file %User Temp%/update.exe, which is detected as TROJ_DROPR.VTG. It then executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

Upon execution, it opens the non-malicious dropped file %User Temp%\{malware filename}.doc in order to hide its malicious routines from the user.

  SOLUTION

Minimum Scan Engine: 8.900

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Remove the malware/grayware file that dropped/downloaded TROJ_ARTIEF.LAS

    TROJ_DROPR.VTG

Step 3

Search and delete this file

[ Learn More ]
There may be some component 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.

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_ARTIEF.LAS. 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

Download and apply these security patches Refrain from using these products until the appropriate patches have been installed. Trend Micro advises users to download critical patches upon release by vendors. Microsoft Security Bulletin MS10-087


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