Analysis by: Karl Dominguez
 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

It takes advantage of the Use-after-free vulnerability in the Peer Objects component in Microsoft Internet Explorer to download possibly malicious files.

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

As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: Varies
File Type: HTML, HTM
Memory Resident: No
Initial Samples Received Date: 29 Nov 2010
Payload: Disables services

Arrival Details

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

Download Routine

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

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

  • http://www.{BLOCKED}4.com/letter/o.exe

As of this writing, the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine: 8.900
VSAPI PATTERN File: 7.656.10
VSAPI PATTERN Date: 29 Nov 2010
VSAPI PATTERN Date: 11/29/2010 12:00:00 AM
VSAPI OPR PATTERN File: 7.657.00
VSAPI OPR PATTERN Date: 29 Nov 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

Close all opened browser windows

Step 3

Scan your computer with your Trend Micro product to delete files detected as JS_EXPLOIT.SM1. 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.  MS10-018


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