BKDR_PLUGX.DO

 Analysis by: Jimelle Monteser

 ALIASES:

Backdoor.Win32.Plugx (Ikarus), Backdoor.Korplug (Norton)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware, Downloaded from the Internet


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 executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

253,952 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

29 Nov 2013

Payload:

Drops files, Terminates processes, Compromises system security, Others

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 creates the following folders:

  • %All Users Profile%\SxS
  • %All Users Profile%\Camera

(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)

It stays memory-resident by injecting codes into the following processes:

  • msiexec.exe
  • svchost.exe

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CLASSES_ROOT\FAST

HKEY_LOCAL_MACHINE\FAST

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Setttings\
5.0\User Agent

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Setttings\
5.0\User Agent\Post Platform

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Setttings\
User Agent

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Setttings\
User Agent\Post Platform

It adds the following registry entries:

HKEY_CLASSES_ROOT\FAST
CLSID = "{random values}"

HKEY_LOCAL_MACHINE\FAST
CLSID = "{random values}"

It creates the following registry entry(ies) to bypass Windows Firewall:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%User Temp%\CamMute.exe = "%User Temp%\CamMute.exe:*:Enabled:Camera Mute Control Service for ThinkPad"

Propagation

This backdoor does not have any propagation routine.

Backdoor Routine

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

  • Copy, move, rename, delete files
  • Create directories
  • Create files
  • Enumerate files
  • Execute files
  • Get drive information
  • Get file information
  • Open and modify files
  • Log keystrokes and active window
  • Enumerate TCP and UDP connections
  • Enumerate network resources
  • Set TCP connection state
  • Lock workstation
  • Log off user
  • Restart/Reboot/Shutdown system
  • Display a message box
  • Perfrom port mapping
  • Enumerate processes
  • Get process information
  • Terminate processes
  • Enumerate registry keys
  • Create registry keys
  • Delete registry keys
  • Copy registry keys
  • Enumerate registry entries
  • Modify registry entries
  • Delete registry values
  • Screen capture
  • Delete services
  • Enumerate services
  • Get service information
  • Modify services
  • Start services
  • Perform remote shell
  • Connect to a database server and execute SQL statement
  • Host Telnet server

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

  • http://{BLOCKED}e.{BLOCKED}tingrecovery.net:443/update?id={malware ID}

Dropping Routine

This backdoor drops the following files:

  • %User Temp%\CamMute.exe
  • %User Temp%\CommFunc.dll - detected as BKDR_PLUGX.DO
  • %User Temp%\CommFunc.jax - detected as BKDR_PLUGX.DO
  • %All Users Profile%\Camera\CamMute.exe
  • %All Users Profile%\Camera\CommFunc.dll - detected as BKDR_PLUGX.DO
  • %All Users Profile%\Camera\CommFunc.jax - detected as BKDR_PLUGX.DO
  • %All Users Profile%\SxS\bug.log

(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, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.. %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)

It executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

Information Theft

This backdoor accepts the following parameters:

  • -k (bypass firewall)

Other Details

This backdoor deletes the initially executed copy of itself

NOTES:

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

10.440.08

FIRST VSAPI PATTERN DATE:

29 Nov 2013

VSAPI OPR PATTERN File:

10.441.00

VSAPI OPR PATTERN Date:

29 Nov 2013

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

Delete this registry key

[ 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_CLASSES_ROOT
    • FAST
  • In HKEY_LOCAL_MACHINE
    • FAST
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Setttings\5.0
    • User Agent
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Setttings
    • User Agent

Step 4

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\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %User Temp%\CamMute.exe = "%User Temp%\CamMute.exe:*:Enabled:Camera Mute Control Service for ThinkPad"

Step 5

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %All Users Profile%\SxS
  • %All Users Profile%\Camera

Step 6

Search and delete these files

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %User Temp%\CamMute.exe

Step 7

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


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