Analysis by: Michael Cabel
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It takes advantage of software vulnerabilities in certain software to drop malicious files. It executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

Once a malware successfully exploits the said vulnerability, it causes certain actions to be done on the system.

  TECHNICAL DETAILS

File Size: 106,580 bytes
File Type: DOC
Memory Resident: No
Initial Samples Received Date: 03 Mar 2012
Payload: Drops files

Arrival Details

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Dropping Routine

This Trojan takes advantage of unknown vulnerabilities in the following software to drop malicious files:

  • Microsoft Word

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

  • Vulnerability in certain versions of Adobe Flash Player

It executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

Other Details

Once a malware successfully exploits the said vulnerability, it causes the following actions to be done on the system:

  • Drop and execute a file named JUCHECK.EXE in the user temporary folder. This file is detected as BKDR_YAYIH.AB.
  • Drop and execute an embedded SWF file, detected as SWF_DLOADR.AC, on the system root directory as MAPMO.SWF

More information on this vulnerability can be found below:

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 8.814.02
FIRST VSAPI PATTERN DATE: 03 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 TROJ_MDROPR.AC

    SWF_DLOADR.AC
    BKDR_YAYIH.AB

Step 3

Scan your computer with your Trend Micro product to delete files detected as TROJ_MDROPR.AC. 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 4

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. http://www.adobe.com/support/security/bulletins/apsb12-03.html


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