Analysis by: Christopher Daniel So
ALIASES:

VirTool:JS/Obfuscator (Microsoft)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This Trojan executes when a user accesses certain websites where it is hosted.

It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system. As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 6,709 bytes
File Type: JS
Memory Resident: No
Initial Samples Received Date: 06 Apr 2011
Payload: Downloads files

Arrival Details

This Trojan executes when a user accesses certain websites where it is hosted.

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}ox.cz.cc/exe.php?exp=HCP&key=fcfe7c10d4f05fa29b45456408269fdc&u=dima

It takes advantage of the following software vulnerabilities to download possibly malicious files:

  • Vulnerability in the way Microsoft Windows Help and Support Center in Windows XP and Windows Server 2003 handle escape sequences

It saves the files it downloads using the following names:

  • %User Temp%\file.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 then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

As of this writing, the said sites are inaccessible.

Other Details

For more information on the aforementioned vulnerabilities, please see the following pages:

  • Microsoft Security Bulletin MS10-042

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: 7.954.07
FIRST VSAPI PATTERN DATE: 06 Apr 2011
VSAPI OPR PATTERN File: 7.955.00
VSAPI OPR PATTERN Date: 06 Apr 2011

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

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%\file.exe

Step 3

Scan your computer with your Trend Micro product to delete files detected as JS_EXPLOIT.HBA. 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 4

Download and apply this security patch Refrain from using these products until the appropriate patches have been installed. Trend Micro advises users to download critical patches upon release by vendors.


Did this description help? Tell us how we did.