BKDR_DELF.XXVS

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

It executes commands from a remote malicious user, effectively compromising the affected system. However, as of this writing, the said sites are inaccessible.

It deletes the initially executed copy of itself.

Arrival Details

This Backdoor 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 drops the following copies of itself into the affected system and executes them:

• %AppDataLocal%\Svdlm.exe

(Note: %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local on Windows Vista, 7, and 8.)

It adds the following processes:

• %AppDataLocal%\Svdlm.exe \melt {full file path of originally executed copy}

(Note: %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local on Windows Vista, 7, and 8.)

It displays the following fake error messages:

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Adlm = "%AppDataLocal%\Svdlm.exe"

Backdoor Routine

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

• Check Server/Client Connectivity
• Install/Uninstall/Update Server
• Execute/Terminate Server
• Execute/Terminate/List Processes
• List and Control Available Windows (Maximize, Minimize, Close, Hide, Disable Buttons)
• Activate/Deactivate Keylogger
• Visit Arbitrary websites
• Control Mouse (Disable, Enable, Shake, Freeze, Move)
• Enable/Disable the Start Button
• Display Arbitrary Message Boxes
• Manage Files and/or Folders(List, Create, Delete, Rename, Move, Hide, Unhide, Copy, Cut, Paste, Search)
• Traverse Directories (Recent, Documents, Desktop, Windows, System, Current)
• Change User
• Perform chat
• Perform Screen Capture
• List and control Webcams
• Upload/Download Arbitrary Files (Pause, Resume)
• Get Thumbnails
• Get Audio
• Get/Set Clipboard data
• List available drivers
• Perform DDOS (TCP, UDP)
• Gather the following information and send to the C&C server:
  • System Information
  • Computer Name
  • Host Name
  • Google Talk Credentials
  • Keylogs
  • Server Information

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

• {BLOCKED}o.{BLOCKED}s.org:1431

However, as of this writing, the said sites are inaccessible.

Other Details

This Backdoor deletes the initially executed copy of itself