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BKDR_GHOST.LRK

March 13, 2014
 Analysis by: Christopher Daniel So
 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


This malware is dropped by the malicious .DOC file, TROJ_EXPLOYT.AGH, which takes advantage of the mass stabbing incident in Kunming, China in early March 2014.

To get a one-glance comprehensive view of the behavior of this Backdoor, refer to the Threat Diagram shown below.

This Backdoor may be dropped by other malware.

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

It gathers certain information on the affected computer.

  TECHNICAL DETAILS

File Size:

122,368 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

04 Mar 2014

Payload:

Connects to URLs/IPs, Drops files, Steals information

Arrival Details

This Backdoor may be dropped by the following malware:

Installation

This Backdoor drops the following files:

  • %Application Data%\Micbt\IconConfigBt.DAT - Configuration File
  • %User Temp%\win_32.sys - encryption table

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

It drops the following copies of itself into the affected system:

  • %Application Data%\Micbt\wininit.exe

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

It creates the following folders:

  • %Application Data%\Micbt

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

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%\wininit.lnk

(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 XP, or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

Other System Modifications

This Backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\DbxUpdateBT

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\DbxUpdateBT
Mark = "{data from IconConfigBt.DAT}"

Backdoor Routine

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

  • File Manipulation
  • Capture Screen
  • Log Keyboard Strokes
  • Download and Executre Arbitrary Files
  • Retrieves Cookies
  • Record Audio
  • Remote Shell Command
  • Process Manipulation

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

  • {BLOCKED}4.{BLOCKED}s.net:80

Information Theft

This Backdoor gathers the following information on the affected computer:

  • OS Version
  • Username
  • Computer Name
  • Memory Size (RAM)
  • Network Username
  • Hardware Information (Processor)
  • Drive Information

Other Details

This Backdoor checks for the presence of the following process(es):

  • 360Tray.exe
  • 360SD.exe

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

10.642.08

FIRST VSAPI PATTERN DATE:

04 Mar 2014

VSAPI OPR PATTERN File:

10.659.00

VSAPI OPR PATTERN Date:

11 Mar 2014

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 2

Remove the malware/grayware file that dropped/downloaded BKDR_GHOST.LRK. (Note: Please skip this step if the threat(s) listed below have already been removed.)

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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_CURRENT_USER\Software\Microsoft\Windows
    • DbxUpdateBT

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.  
  • %Application Data%\Micbt

Step 6

Search and delete this file

[ 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 Startup%\wininit.lnk
  • %User Temp%\win_32.sys

Step 7

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