JS_DLOADR.BHD

 Analysis by: Jasen Sumalapao

 ALIASES:

Trojan:JS/BlacoleRef.W (Microsoft), Trojan-Downloader.JS.Agent.gtm (Kaspersky)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It 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 executes downloaded files whose malicious routines are exhibited by the affected system. As of this writing, the said sites are inaccessible.

This is the Trend Micro detection for Web pages that were compromised through the insertion of a certain IFRAME tag. Once a user visits an affected Web page, this HTML script launches a hidden IFRAME that connects to a malicious URL.

  TECHNICAL DETAILS

File Size:

4,186 bytes

File Type:

JS, HTML, HTM

Initial Samples Received Date:

07 Aug 2012

Arrival Details

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

It 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 connects to the following website(s) to download and execute a malicious file:

  • http://{BLOCKED}litia.ru:8080/forum/showthread.php?page=5fa58bce769e5c2c

It executes downloaded files :

  • %Application Data%\KB{random numbers}.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)

whose malicious routines are exhibited by the affected system.

As of this writing, the said sites are inaccessible.

Other Details

This is the Trend Micro detection for Web pages that were compromised through the insertion of a certain IFRAME tag.

Once a user visits an affected Web page, this HTML script launches a hidden IFRAME that connects to a malicious URL.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

9.308.08

FIRST VSAPI PATTERN DATE:

07 Aug 2012

VSAPI OPR PATTERN File:

9.309.00

VSAPI OPR PATTERN Date:

08 Aug 2012

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

Remove malware/grayware files dropped/downloaded by JS_DLOADR.BHD

    • %Application Data%\KB{random numbers}.exe

Step 3

Scan your computer with your Trend Micro product to delete files detected as JS_DLOADR.BHD. 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.


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