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BKDR_XTRAT.B
Malware type: Backdoor
Destructive: No
Platform: Windows 2000, Windows XP, Windows Server 2003
Encrypted: No
In the wild: Yes

Overview


Infection Channel: Downloaded from the Internet, Dropped by other malware

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 steals system information. It logs a user's keystrokes to steal information.

Technical Details


File size: 999,808 bytes
File type: EXE
Memory resident: Yes
Initial samples received date: 26 Oct 2012
Payload: Compromises system security, Logs keystrokes, Connects to URLs/IPs, Steals 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 drops the following non-malicious files:

  • %User Temp%\2.ico
  • %User Temp%\barrage.doc
  • %User Temp%\.exe

(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.)

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

  • %User Temp%\Word.exe

(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.)

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

  • jhfjgj

It injects threads into the following normal process(es):

  • %System%\sethc.exe

(Note: %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.)

Autostart Technique

This backdoor drops the following shortcut pointing to its copy in the User Startup folder to enable its automatic execution at every system startup:

  •         .lnk

Other System Modifications

This backdoor adds the following registry entries as part of its installation routine:

HKEY_CLASSES_ROOT\hj2120431795e.dsz
(Default) = {Random HEX Values}

HKEY_CURRENT_USER\Software\jhfjgj
??????????????????????????? = OK

HKEY_CURRENT_USER\Software\jhfjgj
ServerStarted = {Date and Time of Execution}

HKEY_CURRENT_USER\Software\WinRAR SFX
C%%DOCUME~1%{User Name}%LOCALS~1%Temp = "%User Temp%"

HKEY_CURRENT_USER\Software\XtremeRAT
Mutex = jhfjgj

Backdoor Routine

This backdoor opens the following port(s) where it listens for remote commands:

  • TCP port 1500

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

  • {BLOCKED}g.{BLOCKED}p.org

Information Theft

This backdoor steals system information.

It logs a user's keystrokes to steal information.

Stolen Information

This backdoor saves the stolen information in the following file:

  • %Application Data%\Microsoft\Windows\jhfjgj.dat

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)

Solution


Minimum scan engine: 9.300
First VSAPI Pattern File: 9.488.04
First VSAPI Pattern Release Date: 26 Oct 2012
VSAPI OPR Pattern Version: 9.489.00
VSAPI OPR Pattern Release Date: 27 Oct 2012

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

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
    • hj2120431795e.dsz
  • In HKEY_CURRENT_USER\Software
    • jhfjgj
  • In HKEY_CURRENT_USER\Software
    • WinRAR SFX
  • In HKEY_CURRENT_USER\Software
    • XtremeRAT

Step 4

Search and delete this file

[ Learn more ]
There may be some component 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%\2.ico
  • %User Temp%\barrage.doc
  • %User Temp%\.exe
  • %User Startup%\            .lnk
  • %Application Data%\Microsoft\Windows\jhfjgj.dat

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_XTRAT.B. 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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Analysis By: Michael Cabel

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