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JS_REDIR.BZ

March 11, 2010
 Analysis by: adel
 PLATFORM:

Windows 98, ME, NT, 2000, XP, Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW


Trend Micro has flagged this malicious JavaScript as noteworthy due to the increased potential for damage, propagation, or both, that it possesses. Specifically, it exploits a vulnerability in several versions of Internet Explorer.

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

This Trojan may be unknowingly downloaded by a user while visiting malicious websites. It may be hosted on a website and run when a user accesses the said website.

It takes advantage of unknown vulnerabilities in certain software to download malicious files.

  TECHNICAL DETAILS

File Type:

Script

Memory Resident:

No

Initial Samples Received Date:

10 Mar 2010

Payload:

Downloads files

Arrival Details

This Trojan may be unknowingly downloaded by a user while visiting malicious websites.

It may be hosted on a website and run when a user accesses the said website.

Download Routine

This Trojan takes advantage of unknown vulnerabilities in the following software to download malicious files:

  • Microsoft Internet Explorer Invalid Pointer Reference Remote Code Execution

After successfully exploiting the said vulnerability, this malware connects to the following URLs to possibly download other malicious files:

  • http://www.{BLOCKED}.co.uk/img/menu.gif

It saves the files it downloads using the following names:

  • %User Temp%\vac.gif - encrypted GIF file detected as TROJ_EMBED.BF

(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.)

Other Details

Based on analysis of the codes, it has the following capabilities:

  • It decrypts the downloaded file, saves it and executes it to the following location: %Application Data%\rnd.exe - detected as TROJ_DRPR.BA

(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:

8.900

FIRST VSAPI PATTERN FILE:

6.910.05

FIRST VSAPI PATTERN DATE:

10 Mar 2010

VSAPI OPR PATTERN File:

6.911.00

VSAPI OPR PATTERN Date:

10 Mar 2010

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

Remove malware files dropped/downloaded by JS_REDIR.BZ

Step 3

Close all opened browser windows

Step 4

Scan your computer with your Trend Micro product to delete files detected as JS_REDIR.BZ. 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 5

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.


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