Analysis by: Sabrina Lei Sioting
 Modified by: Karl Dominguez
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This backdoor may be dropped by other malware.

It connects to certain websites to send and receive information.

  TECHNICAL DETAILS

File Size: Varies
File Type: PE
Memory Resident: Yes
Initial Samples Received Date: 12 Aug 2011
Payload: Steals information

Arrival Details

This backdoor may be dropped by the following malware:

  • TROJ_ARTIEF.AE

Installation

This backdoor drops the following files:

  • %Windows%\wdmaud.drv - also detected as BKDR_AGENTT.S
  • %Windows%\netv.dat - dump of net view command. This file will be deleted by the malware after execution
  • %Windows%\ipcon.dat - dump of ipconfig command. This file will be deleted by the malware after execution

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

Its DLL component is injected to the following process(es):

  • Explorer.exe

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • my_horse_mutex_jd2_new

Other Details

This backdoor connects to the following website to send and receive information:

  • http://www.{BLOCKED}bit.com/ko/upload.apsx?filename={MAC Address}_{IP address}.jpg
  • http://www.{BLOCKED}bit.com/ko/upload.apsx?filename={value}&filename={MAC Address}_{IP address}.jpg
  • http://www.{BLOCKED}bit.com/ko/order/{MAC Address}_{IP address}.jpg

NOTES:

It steals the following information from the affected system:

  • Address book contents
  • Computer name
  • Computers in the current domain
  • Email user names and passwords
  • IP Configuration
  • Language
  • Proxy server
  • Running processes
  • System directory
  • System version
  • User name

It emails the stolen information to the following addresses:

  • {BLOCKED}tmail002@aol.com
  • {BLOCKED}md009@aol.com
  • {BLOCKED}ero009@aol.com

It can perform the following routine:

  • Download other files
  • Execute cmd commands

It uses the following custom User-Agent for its communication with the remote URLs:

  • MyAgent
  • mydownload

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: 8.350.04
FIRST VSAPI PATTERN DATE: 12 Aug 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 the malware/grayware file that dropped/downloaded BKDR_AGENTT.S

     TROJ_ARTIEF.AE

Step 3

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_AGENTT.S. 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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