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BKDR_XTRAT.JS

November 14, 2012
 ALIASES:

Mal/Agent-AFT (Sophos), W32/Agent.AFT (Fortinet), Worm.Win32.Ainslot (Ikarus), Worm:Win32/Ainslot.J (Microsoft), a variant of MSIL/Injector.QR trojan (NOD32), Trojan.ADH.2 (Norton)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • 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 executes then deletes itself afterward.

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

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

  TECHNICAL DETAILS

File Size:

132,880 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

13 Nov 2012

Payload:

Compromises system security, 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 executes then deletes itself afterward.

It injects itself into the following processes as part of its memory residency routine:

  • iexplorer.exe
  • svchost.exe

Other System Modifications

This backdoor adds the following registry entries:

HKEY_CURRENT_USER\Software\XtremeRAT
Mutex = "fdgdfgdfg"

HKEY_CURRENT_USER\Software\fdgdfgdfg
ServerStarted = "{Date and Time}"

Backdoor Routine

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

  • TCP port 8888

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

  • http://{BLOCKED}d.{BLOCKED}o.org:50002/1411.functions
  • http://{BLOCKED}a.{BLOCKED}e.nu:50002/1411.functions

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

Download Routine

This backdoor connects to the following URL(s) to download its component file(s):

  • http://www.{BLOCKED}ad.{BLOCKED}supdate.com/msdownload/update/v3/static/trustedr/en/authrootseq.txt

Information Theft

This backdoor steals system information.

It logs a user's keystrokes to steal information.

Stolen Information

The stolen information is saved in the following file:

  • %Application Data%\Microsoft\Windows\fdgdfgdfg.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:

9.200

FIRST VSAPI PATTERN FILE:

9.524.02

FIRST VSAPI PATTERN DATE:

13 Nov 2012

VSAPI OPR PATTERN File:

9.525.00

VSAPI OPR PATTERN Date:

14 Nov 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_CURRENT_USER\Software\fdgdfgdfg
    • ServerStarted
  • In HKEY_CURRENT_USER\Software\XtremeRAT
    • Mutex

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

Step 5

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

Step 6

Scan your computer with your Trend Micro product to delete files detected as BKDR_XTRAT.JS. 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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