Analysis by: Michael Cabel

ALIASES:

Symantec: Trojan.Malscript; Mcafee: Exploit-CVE2010-3962; Microsoft: Exploit:Win32/CVE-2010-3962.A

 PLATFORM:

Windows 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

Once a malware successfully exploits the said vulnerability, it causes certain actions to be done on the system. As of this writing, the said sites are inaccessible.

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 software vulnerabilities to allow a remote user or malware/grayware to download files.

  TECHNICAL DETAILS

File Size: Varies
File Type: JS
Memory Resident: No
Initial Samples Received Date: 16 Dec 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 allow a remote user or malware/grayware to download files:

  • CVE-2010-3962

Other Details

More information on this vulnerability can be found below:

NOTES:

Once a malware successfully exploits the said vulnerability, it causes the following actions to be done on the system:

  • Attempts to download a possibly malicious file from the following web site:
    • http://login.live.com.{BLOCKED}word.com/update.exe

As of this writing, the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: 7.704.14
FIRST VSAPI PATTERN DATE: 17 Dec 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_SHELLCOD.GU. 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 these security patches Refrain from using these products until the appropriate patches have been installed. Trend Micro advises users to download critical patches upon release by vendors.  http://www.microsoft.com/technet/security/bulletin/MS10-090.mspx


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