JS_BLACOLE.ISH

June 08, 2013
 Analysis by: Anthony Joe Melgarejo
 ALIASES:

Exploit:JS/Blacole.GB (Microsoft), JS/Exploit-Blacole.a!heur (McAfee), JS/Exploit (AVG), JS/Kryptik.ALE trojan (ESET)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

 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 hosted on a website and run when a user accesses the said website.

  TECHNICAL DETAILS

File Size:

107,088 bytes

File Type:

HTML, HTM

Memory Resident:

No

Initial Samples Received Date:

08 Jun 2013

Arrival Details

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

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}s.net/news/readers-sections.php?jnlp=8b81c0983a
  • http://{BLOCKED}s.net/news/readers-sections.php?{variable URI}

It saves the files it downloads using the following names:

  • %User Temp%\{random numbers}.exe

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

NOTES:

The {variable URI} depends on the browser plugin in the affected system.

Here are some examples of the {variable URI}:

  • hvucuaz=abelzaj&ktaq=fsdcxzf
  • gszjhwrs=uyk&;cekvyjcy=ambkahq
  • wf=1f:33:1k:30:1f&ke=1n:2w:1n:1g:30:1f:1o:1n:1i:2v&a=1f&wr=c&oi=j&;jopa=8799859
  • sf=1f:33:1k:30:1f&ee=1n:2w:1n:1g:30:1f:1o:1n:1i:2v&l=1f&zm=u&zi=p&jopa=2924946

After its download routine, it redirects the browser to the following site to trick users that they are visiting a legitimate website.

  • http://google.com/search?q=bbb

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.966.05

FIRST VSAPI PATTERN DATE:

08 Jun 2013

VSAPI OPR PATTERN File:

9.967.00

VSAPI OPR PATTERN Date:

08 Jun 2013

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Close all opened browser windows

Step 3

Search and delete these files

[ Learn More ]
There may be some 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.
  • %User Temp%\{random numbers}.exe

Step 4

Scan your computer with your Trend Micro product to delete files detected as JS_BLACOLE.ISH. 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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