Threat Encyclopedia

JS_PLOIT.BC

Malware type: JavaScript

Aliases: Trojan-Downloader.JS.Agent.eg (Kaspersky), JS/Exploit-BO.gen (McAfee), Downloader (Symantec), JS/Dldr.Small.CR.2 (Avira), Troj/Wafer-B (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:

Medium

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_PLOIT.BC Behavior Diagram

Malware Overview

This malicious JavaScript can arrive via the Internet when an unsuspecting user visits the malicious Web page that hosts it. It can also arrive as a file dropped or downloaded by another malware.

It exploits a new vulnerability in Internet Explorer (IE) that allows it connects to the URL {BLOCKED}rvhgwuzc.biz/dl/oaderadv499.exe to download a malicious file detected by Trend Micro as TROJ_AGENT.FGD. The routines of the downloaded Trojan are then exhibited onto the affected system.

The said vulnerability targets IEs WebViewFolderIcon ActiveX control. More information can be found in this link.

Note that this detection is a zero-day exploit because it attacks a software vulnerability for which the vendor has not released a patch. This may pose as a dangerous situation in which a lot of computers may be affected due to the availability of the exploit code, and the fact that there is no available patch for the vulnerability.

For additional information about this threat, see:

Description created: Sep. 30, 2006 12:29:49 AM GMT -0800


TECHNICAL DETAILS


File type: Script

Size of malware: 2,532 Bytes

Initial samples received on: Sep 30, 2006

Related toTROJ_AGENT.FGD

Payload 1: Downloads files

Details:

This malicious JavaScript can arrive via the Internet when an unsuspecting user visits the malicious Web page that hosts it. It can also arrive as a file dropped or downloaded by another malware.

It exploits a new vulnerability in Internet Explorer (IE) that allows it connects to the URL {BLOCKED}rvhgwuzc.biz/dl/oaderadv499.exe to download a malicious file detected by Trend Micro as TROJ_AGENT.FGD. The routines of the downloaded Trojan are then exhibited onto the affected system.

The said vulnerability targets IE�s WebViewFolderIcon ActiveX control. More information can be found in this link.

Note that this detection is a zero-day exploit because it attacks a software vulnerability for which the vendor has not released a patch. This may pose as a dangerous situation in which a lot of computers may be affected due to the availability of the exploit code, and the fact that there is no available patch for the vulnerability.

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

Analysis By: Brian Cayanan


SOLUTION


Minimum scan engine version needed: 7.500

Pattern file needed: 3.803.00

Pattern release date: Sep 30, 2006


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: To fully remove all associated malware, perform the clean solution for TROJ_AGENT.FGD. Also, close all instances of Internet Explorer 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

If you are currently running in safe mode, please restart your computer normally before performing the following solution.

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

Vulnerability Workaround

This malware exploits known vulnerability in Windows. Do the workaround fix supplied by Microsoft. 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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