BKDR_POISON.AB

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

It deletes itself after execution.

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 drops the following copies of itself into the affected system:

• %User Profile%\Application Data\LMKPlayer.exe (for accounts without Admin Rights)
• %System%:LMKPlayer.exe (for accounts with Admin Rights)
• %User Profile%\AppData\Roaming:LMKPlayer.exe (for Windows Vista/Windows 7 only)

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.. %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 adds the following mutexes to ensure that only one of its copies runs at any one time:

• 2j8sji2q9

Autostart Technique

This backdoor creates the following registry entries to enable automatic execution of dropped component at every system startup:

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
AdobeYestr LKPlayer = "%User Profile%\Application Data\LMKPlayer.exe" (for accounts without Admin Rights)

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
AdobeYestr LKPlayer = "%System%:LMKPlayer.exe" (for accounts with Admin Rights)

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
AdobeYestr LKPlayer = "%User Profile%\AppData\Roaming:LMKPlayer.exe" (for Windows Vista/Windows 7 only)

Backdoor Routine

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

• Send system information (Lan IP, Wan IP, Computer name, Username, Account Type, OS)
• Send hardware information (CPU speed, Memory)
• Manage Files (Search, Download, Upload, Execute, Rename, Delete)
• Manage Registries (Search, Modify, Delete, Rename, Create)
• Manage Processes (View, Kill, Suspend, Unload Module)
• Manage Services (View, Start, Stop, Edit, Install, Uninstall)
• Manage Devices (View, Enable, Disable, Remove)
• Manage Windows
• Relay server
• View,copy and uninstall applications
• View active ports
• Perform a shell command
• Download and inject remote codes to legitimate processes
• Log keystrokes and active window
• Capture screenshots
• View webcam activity
• Listen to microphone audio
• Update, Uninstall, Restart the malware
• Retrieve cached passwords and hashes

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

• {BLOCKED}.{BLOCKED}.55.35:443
• {BLOCKED}.{BLOCKED}.55.35:80

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

Other Details

This backdoor deletes itself after execution.

NOTES:

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 if the said process containing its backdoor routines.