Threat Encyclopedia

JS_MULEX.C

Malware type: JavaScript

Aliases: Trojan-Downloader.JS.Agent.pm (Kaspersky), Exploit-DXMEDIA (McAfee), HTML/Dldr.Agen.N.15 (Avira), Troj/Mulex-A (Sophos),

In the wild: Yes

Destructive: No

Language: English

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

Encrypted: No

Overall risk rating:

Reported infections:

Damage potential:

High

Distribution potential:

Medium

Description: 

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

JS_MULEX.C Behavior Diagram

Malware Overview

This malicious JavaScript is hosted on a certain URL.

It downloads, saves, and executes a file detected by Trend Micro as TSPY_AGENT.AAWC. As a result, routines of the downloaded spyware may be exhibited on the affected system. Variants of this malicious JavaScript perform the said routine by exploiting certain browser vulnerabilities.

For additional information about this threat, see:

Description created: Sep. 10, 2007 3:32:09 AM GMT -0800


TECHNICAL DETAILS


File type: Script

Size of malware: 28,365 Bytes

Initial samples received on: Sep 10, 2007

Payload 1: Downloads files

Details:

Infection Points

This malicious JavaScript is hosted on the URL http://{BLOCKED}.{BLOCKED}.72.200/index.php.

Download Routines

This JavaScript downloads a file from the URL http://{BLOCKED}.{BLOCKED}.72.200/exe.php. It then saves and executes this file as C:\U.EXE. Trend Micro detects the downloaded file as TSPY_AGENT.AAWC.

As a result, routines of the downloaded spyware may be exhibited on the affected system. Variants of this malicious JavaScript perform the said routine by exploiting certain browser vulnerabilities.

Variant Information

This JavaScript obfuscates its file structure. It has the following MD5 hash(es):

    62356fadee24b5b1ad102871f658015e

Affected Platforms

This JavaScript runs on Windows 98, ME, NT, 2000, XP, and Server 2003.

Analysis By: Julius Caezar R. Dizon

Revision History:

First pattern file version: 4.709.00
First pattern file release date: Sep 10, 2007

SOLUTION


Minimum scan engine version needed: 8.000

Pattern file needed: 4.709.00

Pattern release date: Sep 10, 2007


Important note: The "Minimum scan engine" refers to the earliest Trend Micro scan engine version guaranteed to detect this threat. However, Trend Micro strongly recommends that you update to the latest version in order to get comprehensive protection. Download the latest scan engine here.

Solution:

(Note: Close all Internet Explorer windows before proceeding with the solution below.)

Important Windows ME/XP Cleaning Instructions

Users running Windows ME and XP must disable System Restore to allow full scanning of infected computers.

Users running other Windows versions can proceed with the succeeding solution set(s).

Running Trend Micro Antivirus

Scan your computer with Trend Micro antivirus and delete files detected as JS_MULEX.C. To do this, Trend Micro customers must download the latest virus pattern file and scan their computers. Other Internet users can use HouseCall, the Trend Micro online threat scanner.

Applying Patches

This malware exploits known vulnerabilities in Internet Explorer. Download and install the latest fix patches. Refrain from using this product until the appropriate patch has been installed. Trend Micro advises users to download critical patches upon release by vendors.




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