PLATFORM:

Windows

 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 backdoor may be dropped by other malware.

It executes commands from a remote malicious user, effectively compromising the affected system.

  TECHNICAL DETAILS

File Size: 270,318 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 13 Nov 2014
Payload: Steals information, Connects to URLs/IPs

Arrival Details

This backdoor may be dropped by the following malware:

  • TROJ_EXPLOYT.PEL

Installation

This backdoor drops the following component file(s):

  • %Application Data%\Micbt\IconConfigBt.DAT - configuration file
  • %User Temp%\win_32.sys - encryption table
  • %Application Data%\Micbt\DEL.VBS - used to execute RasTls.exe

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

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

  • %Application Data%\Micbt\RasTls.exe

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It creates the following folders:

  • %Application Data%\Micbt

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

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%\RasTls.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, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)

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 URL(s) to send and receive commands from a remote malicious user:

  • {BLOCKED}dia.imbbs.in
  • {BLOCKED}on355.vicp.cc

Information Theft

This backdoor gathers the following data:

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

  SOLUTION

Minimum Scan Engine: 9.700

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

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

     
    • TROJ_EXPLOYT.PEL

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 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.

Step 7

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