JS_DLOADER.FIS

January 16, 2010
 Analysis by: adel
 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

This JavaScript has received attention from independent media sources and/or other security firms.

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

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 connects to certain URLs. It may do this to remotely inform a malicious user of its installation. It may also do this to download possibly malicious files onto the computer, which puts the computer at a greater risk of infection by other threats. It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

  TECHNICAL DETAILS

File Size:

17,310 bytes

File Type:

Script

Memory Resident:

No

Initial Samples Received Date:

14 Jan 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 connects to the following malicious URLs:

  • http://{BLOCKED}ftpaccess.cc/demo/ad.jpg

It takes advantage of the following software vulnerabilities to download possibly malicious files:

It saves the files it downloads using the following names:

  • %Application Data%\a.exe - detected as TROJ_HYDRAQ.SMA

(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.)

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

  SOLUTION

Minimum Scan Engine:

8.900

FIRST VSAPI PATTERN FILE:

6.774.01

FIRST VSAPI PATTERN DATE:

14 Jan 2010

VSAPI OPR PATTERN File:

6.775.00

VSAPI OPR PATTERN Date:

16 Jan 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

Remove malware files dropped/downloaded by JS_DLOADER.FIS

     TROJ_HYDRAQ.SMA

Step 4

Scan your computer with your Trend Micro product to delete files detected as JS_DLOADER.FIS. 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 5

Download and apply this security patch Refrain from using these products until the appropriate patches have been installed. Trend Micro advises users to download critical patches upon release by vendors.

Microsoft Security Bulletin MS10-002


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