Analysis by: Christopher Daniel So
ALIASES:

Exploit:JS/Blacole.AR (Microsoft), JS/Exploit-Blacole.q (Symantec), Trojan-Downloader.JS.Expack.hd (Kaspersky)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet

This Trojan accesses a certain URL to download a JAR file. It then executes the file Inc.class inside the JAR file. The file Inc.class is detected by Trend Micro as JAVA_BLACOLE.BM.

This Trojan may be downloaded unknowingly by a user when visiting malicious website(s).

  TECHNICAL DETAILS

File Size: 17,742 bytes
File Type: HTML, HTM
Initial Samples Received Date: 19 Mar 2012
Payload: Connects to URLs/IPs

Arrival Details

This Trojan may be downloaded unknowingly by a user when visiting the following malicious website(s):

  • http://78.46.194.137:8080/showthread.php?t=d7ad916d1c0396ff

NOTES:

It accesses the following URL to download a JAR file:

  • http://{BLOCKED}.{BLOCKED}.194.137:8080/content/Qai.jar

It then executes the file Inc.class inside the JAR file, passing an encrypted parameter named p. The file Inc.class is detected by Trend Micro as JAVA_BLACOLE.BM. The value of the parameter p when decrypted is http://{BLOCKED}.{BLOCKED}.194.137:8080/q.php?f=7245d&e=0. As of this writing, the said URL is no longer accessible.

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 8.848.07
FIRST VSAPI PATTERN DATE: 19 Mar 2012
VSAPI OPR PATTERN File: 8.849.00
VSAPI OPR PATTERN Date: 19 Mar 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 files dropped/downloaded by JS_BLACOLE.BO

    • JAVA_BLACOLE.BM

Step 3

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