Threat Encyclopedia

JS_SMALL.QT

Malware type: JavaScript

Aliases: JS.Downloader.Trojan (Symantec),

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:

Low

Description: 

Trend Micro threat researchers post findings and analyses on various threats in real-time at the Malware Blog. Users can find more information about this specific threat here.

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

JS_SMALL.QT Behavior Diagram

Malware Overview

This malicious Javascript may be found hosted on a remote Web site. Its link may be found in compromised Web sites, most of which are legitimate.

Once a user opens a compromised Web site, a series of redirections happens, which eventually leads to the download of a file. The downloaded file is detected by Trend Micro as TROJ_ZLOB.CCW.

It then executes the downloaded file. As a result, malicious routines of the downloaded file are exhibited on the affected system.

For additional information about this threat, see:

Description created: May. 10, 2008 12:28:37 AM GMT -0800


TECHNICAL DETAILS


File type: Script

Size of malware: 1,572 Bytes

Initial samples received on: May 9, 2008

Related toTROJ_ZLOB.CCW

Payload 1: Downloads files

Details:

This malicious Javascript may be found hosted on the remote Web site http://{BLOCKED}u.info/f.js. Its link may be found in compromised Web sites, most of which are legitimate.

Once a user opens a compromised Web site, this Javascript redirects to http://{BLOCKED}st.info/go.php?sid=1. A series of redirections follows, which eventually leads to the download of a file. The downloaded file is detected by Trend Micro as TROJ_ZLOB.CCW.

It then executes the downloaded file. As a result, malicious routines of the downloaded file are exhibited on the affected system.

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

Analysis By: Joselito Dela Cruz

Revision History:

First pattern file version: 5.270.13
First pattern file release date: May 10, 2008

SOLUTION


Minimum scan engine version needed: 8.300

Pattern file needed: 5.271.00

Pattern release date: May 11, 2008


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 instances of Internet Explorer before proceeding with the following solution. To fully remove all associated malware, perform the clean solutions for TROJ_ZLOB.CCW.

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_SMALL.QT. 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.




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