Analysis by: adel
 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This JavaScript has received attention from independent media sources and/or other security firms.

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.

  TECHNICAL DETAILS

File Size: 4,096 bytes
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 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://d.{BLOCKED}inrt.us/s.exe

Trend Micro detects the dowloaded file as:

  • TROJ_SASFIS.VR

Other Details

This Trojan is a zero-day exploit for the following vulnerability:

  • Internet Explorer 6 & 7

  SOLUTION

Minimum Scan Engine: 8.900
VSAPI OPR PATTERN File: 6.933.00
VSAPI OPR PATTERN Date: 18 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

Close all opened browser windows

Step 3

Remove malware files dropped/downloaded by JS_SHELLCODE.YY

Step 4

Scan your computer with your Trend Micro product to delete files detected as JS_SHELLCODE.YY. 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. Microsoft Security Bulletin MS10-018


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