Analysis by: Sabrina Lei Sioting
 Modified by: Roland Marco Dela Paz
ALIASES:

Symantec_Beta: Trojan.Mdropper

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This malware exploits a software vulnerability in order to drop a malicious file onto the affected system. It also drops and opens a document file in order to hide its malicious routines.

Once a malware successfully exploits the said vulnerability, it causes certain actions to be done on the system.

  TECHNICAL DETAILS

File Size: 148,511 bytes
Memory Resident: Yes
Initial Samples Received Date: 22 Mar 2011
Payload: Drops files

Installation

This Trojan drops the following non-malicious file:

  • %User Temp%\{malware file name}.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 the following software vulnerabilities to drop malicious files:

Other Details

Once a malware successfully exploits the said vulnerability, it causes the following actions to be done on the system:

  • It drops %User Temp%\update.exe, which is detected as TROJ_DROPPR.CQ.

(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.)

NOTES:
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
FIRST VSAPI PATTERN FILE: 7.924.06
FIRST VSAPI PATTERN DATE: 25 Mar 2011

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 malware files dropped/downloaded by TROJ_ARTIEF.AF

Step 3

Search and delete these files

[ 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.
  • %User Temp%\{malware file name}.doc

Step 4

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

NOTES:


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