Analysis by: Rhena Inocencio
ALIASES:

Trojan.Mdropper (Symantec)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

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

  TECHNICAL DETAILS

File Size: 194,946 bytes
File Type: DOCX
Memory Resident: No
Initial Samples Received Date: 28 Aug 2012

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 non-malicious file:

  • %User temp%\{malware filename}.docx - non-malicious document file that the malware drops and opens to trick users into thinking that the original document file is non-malicious.

Dropping Routine

This Trojan drops the following files:

It takes advantage of the following software vulnerabilities to drop malicious files:

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

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 9.356.01
FIRST VSAPI PATTERN DATE: 29 Aug 2012
VSAPI OPR PATTERN File: 9.357.00
VSAPI OPR PATTERN Date: 29 Aug 2012

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_MDROPPER.NT

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.  
  • %User temp%\{malware filename}.docx

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_MDROPPER.NT. 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.


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