Backdoor.Win32.DARKOMET.NLJ

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 does not have any propagation routine.

It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.

It logs a user's keystrokes to steal information.

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 adds the following folders:

• %User Temp%\dclogs

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

• "%User Startup%\.exe"

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows 2003(32-bit), XP and 2000(32-bit), or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit), 10(64-bit).)

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

• DC_MUTEX-ZSSE2WW

Autostart Technique

This Backdoor drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:

• %User Startup%\.exe → dropped copy of itself

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows 2003(32-bit), XP and 2000(32-bit), or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit), 10(64-bit).)

Propagation

This Backdoor does not have any propagation routine.

Backdoor Routine

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

• Change MSN Messenger status & modify contact list
• DDOS Flooding
• Download and execute files
• Download updated copy of itself
• Empty Recycle Bin
• Get torrent files
• List active windows
• List disk drives
• List webcams and monitor/capture video
• Log keystrokes
• Modify system's host file
• Monitor activity by Remote Desktop Protocol
• Open and close CD-ROM drive door
• Record and play sounds
• Refresh or delete logs
• Refresh Wifi
• Remote shell command
• Shutdown, Restart, Log off or Lock computer
• Start and control chat sessions
• Steal passwords
• Uninstall programs
• Upload files
• Visit arbitrary C&C servers
• It manipulates the following:
  • Browser
  • Clipboard
  • Desktop
  • Dialog Box
  • Files
  • Folders
  • Mouse clicks
  • Processes
  • Registries
  • Services
  • Shutdown button options
  • Start button
  • System clock
  • System tray
  • Taskbar
• It disables the following:
  • Antivirus notification
  • Control Panel
  • Firewall
  • LUA notification
  • Registry Tools
  • Services
  • Task Manager
  • Update notification

It connects to the following websites to send and receive information:

• tcp://{BLOCKED}oss.ddns.net:508

Rootkit Capabilities

This Backdoor does not have rootkit capabilities.

Dropping Routine

This Backdoor drops the following file, into which it saves gathered information:

• %User Temp%\dclogs\{Date}-{Number}.dc

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Information Theft

This Backdoor gathers the following data:

• Admin rights
• Computer name
• Country
• Language
• Memory usage
• OS information
• Username
• Webcam information

It logs a user's keystrokes to steal information.

Other Details

This Backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\DC3_FEXEC

It does not exploit any vulnerability.