TROJ_MDROP.AIG

October 09, 2012
 Analysis by: Lord Alfred Remorin
 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 takes advantage of software vulnerabilities in certain software to drop malicious files.

  TECHNICAL DETAILS

File Size:

232,168 bytes

File Type:

XLS

Memory Resident:

Yes

Initial Samples Received Date:

20 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 files:

  • %User Temp%\4.xls

(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.)

It drops and executes the following files:

  • %User Temp%\~EXCEL.tmp - detected as TROJ_HUPIGO.RUD

(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:

  • Microsoft Excel

NOTES:
Upon execution, this trojan opens the dropped Excel file %User Temp%\4.xls to hide its malicious routines from the user.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

9.336.09

FIRST VSAPI PATTERN DATE:

21 Aug 2012

VSAPI OPR PATTERN File:

9.337.00

VSAPI OPR PATTERN Date:

21 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_MDROP.AIG

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%\4.xls

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_MDROP.AIG. 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.


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