Analysis by: Michael Cabel
 PLATFORM:

Windows 98, ME, NT, 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 arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

It accesses websites to download files. This action allows this malware to possibly add other malware on the affected computer. It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

  TECHNICAL DETAILS

File Size: 14,848 bytes
File Type: PE
Memory Resident: Yes
Initial Samples Received Date: 31 Jul 2010

Arrival Details

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

Download Routine

This Trojan accesses websites to download the following files:

  • http://{BLOCKED}.{BLOCKED}.74.161/mrmun_sgjlgdsjrthrtwg.exe
  • http:/{BLOCKED}.{BLOCKED}.74.165/bat.exe

It saves the files it downloads using the following names:

  • %Temp%\_ex-08.exe - detected as TROJ_BREDOLAB.WV
  • %Application Data%\{Random Characters}.exe - detected as TROJ_FAKEAV.SMES

(Note: %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp or C:\WINNT\Temp.. %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: 6.284.01
FIRST VSAPI PATTERN DATE: 17 Jul 2009
VSAPI OPR PATTERN File: 6.285.00
VSAPI OPR PATTERN Date: 17 Jul 2009

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_WALEDAC.AJE

    TROJ_BREDOLAB.WV
    TROJ_FAKEAV.SMES

Step 3

Scan your computer with your Trend Micro product to delete files detected as TROJ_WALEDAC.AJE. 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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