Analysis by: Mark Joseph Manahan

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel: Spammed via email

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

It does not have any propagation routine.

It executes commands from a remote malicious user, effectively compromising the affected system.

It does not have any downloading capability.

  TECHNICAL DETAILS

File Size: 356,352 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 06 Sep 2012
Payload: Compromises system security, Connects to URLs/IPs

Arrival Details

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

Installation

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

  • kkkeke2ek

It injects codes into the following process(es):

  • explorer.exe

Autostart Technique

This backdoor adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
windows VOscreen = "%System%:voscreen.exe"

Propagation

This backdoor does not have any propagation routine.

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

  • Remote code execution
  • Capture screenshots
  • Retrieve stored passwords
  • View webcam activity
  • Send system information (IP address, computer name, user name, operating system)
  • Displays Messagebox

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • {BLOCKED}rosooo.{BLOCKED}0.org

Download Routine

This backdoor does not have any downloading capability.

NOTES:

It drops a copy of itself to an alternate data stream (ADS) and saves it as %System%:voscreen.exe.

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It queries the default web browser by accessing the following registry entry:

HKEY_CLASSES_ROOT\http\shell\open\command

It then launches a hidden web browser process. (e.g. iexplore.exe) The malware then injects its code in the said process which contains its backdoor routines.

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 9.374.02
FIRST VSAPI PATTERN DATE: 06 Sep 2012
VSAPI OPR PATTERN File: 9.375.00
VSAPI OPR PATTERN Date: 07 Sep 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

Restart in Safe Mode

[ Learn More ]

Step 3

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

 
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • windows VOscreen = "%System%:voscreen.exe"

Step 4

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

NOTES:

Before proceeding to Step 4, Remove added Alternate Data Streams:

  1. Download Streams.exe.
  2. Extract the contents of this file to a location of your choice.
  3. Open a command prompt window. Click Start > Run.

      ・On Windows 98 and ME, type COMMAND, then press Enter.
      ・On Windows NT, 2000, XP, and Server 2003, type CMD, then press Enter.

  4. In the command prompt, type the following, then press Enter: CD {Path where contents of downloaded file was extracted}
  5. Still in the command prompt type the following then press Enter: Streams.exe -d %System%
  6. Type exit then press enter.


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