Analysis by: Abraham Latimer Camba
 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

Infection Channel: Spammed via email, Downloaded from the Internet, Dropped by other malware

This backdoor arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It opens a hidden Internet Explorer window. It executes commands from a remote malicious user, effectively compromising the affected system.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 65,536 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 19 Sep 2012
Payload: Compromises system security

Arrival Details

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

It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

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

  • 5c325aaac

It injects itself into the following processes as part of its memory residency routine:

  • iexplore.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
vmware remotemks = "%System%:vmremotems.exe"

Backdoor Routine

This backdoor opens a hidden Internet Explorer window.

It executes the following commands from a remote malicious user:

  • Capture screen, audio, and webcam
  • Log keystrokes
  • List active ports
  • Manage open windows
  • Manage passwords
  • Manage registry, processes, services, devices, and installed applications
  • Perform multiple simultaneous transfers
  • Perform remote shell
  • Relay server
  • Search files
  • Share servers
  • Update, restart, terminates itself

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

  • https://{BLOCKED}apad.9966.org

Other Details

This backdoor deletes the initially executed copy of itself

NOTES:

This backdoor creates an Alternate Data Stream (ADS) copy of itself and saves it as %System%:vmremotems.exe.

This allows the malware to hide itself from detection. It also allows it to execute whenever the Windows system folder is accessed.

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

  SOLUTION

Minimum Scan Engine: 9.200

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
    • vmware remotemks = "%System%:vmremotems.exe"

Step 4

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_POISON.BMO. 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:

1. Download Streams.exe from this site (http://technet.microsoft.com/en-us/sysinternals/bb897440)

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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