Analysis by: Rhena Inocencio
 PLATFORM:

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

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware

This Trojan may be dropped by other malware.

It is a component of other malware.

  TECHNICAL DETAILS

File Size: 3,939 bytes
File Type: Other
Memory Resident: Yes
Initial Samples Received Date: 10 Apr 2013
Payload: Connects to URLs/IPs, Downloads files

Arrival Details

This Trojan may be dropped by the following malware:

Installation

This Trojan is a component of other malware.

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}cocklameavindustry.in/
    • redirects to http://{BLOCKED}r.dl.{BLOCKED}forge.net/project/stubpe/a/zwz

It saves the files it downloads using the following names:

  • {removable drive letter}:\Thumbs.db - (encrypted file) WORM_ENCMARUE.DA

NOTES:

It decrypts Thumbs.db and saves the decrypted file as follows:

  • %System Root%\Temp\TrustedInstaller.exe - WORM_GAMARUE.DA

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

  SOLUTION

Minimum Scan Engine: 9.300

Step 1

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

Step 2

Remove the malware/grayware file dropped/downloaded by TROJ_GAMARUE.SM

     
    • WORM_ENCMARUE.DA
    • WORM_GAMARUE.DA

Step 3

Scan your computer with your Trend Micro product to delete files detected as TROJ_GAMARUE.SM. 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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