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JS_CRYPTED.SMM

October 09, 2012
 Analysis by: Roland Marco Dela Paz
 Modified by: Christopher Daniel So
 ALIASES:

Trojan-Downloader.JS.Timul.dy (Kaspersky), JS/Crypted.GS.gen (Authentium)

 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 downloads and loads a Java applet. However, the said Java applet is inaccessible.

This Trojan may be hosted on a website and run when a user accesses the said website.

It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system. As of this writing, the said sites are inaccessible.

It inserts an IFRAME tag that redirects users to certain URLs. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

HTML, HTM

Initial Samples Received Date:

24 May 2011

Arrival Details

This Trojan may be hosted on a website and run when a user accesses the said website.

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}.{BLOCKED}.216.203/bu1/news.php?dd={random string}

It saves the files it downloads using the following names:

  • %System%\a.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows 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.

As of this writing, the said sites are inaccessible.

Other Details

This Trojan inserts an IFRAME tag that redirects users to the following URLs:

  • http://{BLOCKED}.{BLOCKED}.216.203/bu1/pdf.php?t=4bec51dc3e3a4

However, as of this writing, the said sites are inaccessible.

NOTES:
It downloads and loads the following Java applet:

  • http://{BLOCKED}1.{BLOCKED}1.216.203/bu1/jjj.jar

However, the said Java applet is inaccessible.

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI OPR PATTERN File:

8.183.00

VSAPI OPR PATTERN Date:

25 May 2011

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

Search and delete this file

[ Learn More ]
There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files and folders in the search result.
  • %System%\a.exe

Step 4

Scan your computer with your Trend Micro product to delete files detected as JS_CRYPTED.SMM. 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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