Analysis by: RomeoD


Windows 98, ME, NT, 2000, XP, Server 2003


  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes


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


File Size: Varies
File Type: PE
Memory Resident: Yes
Payload: Downloads files

Arrival Details

This Trojan may be downloaded from the following remote sites:

  • http://{BLOCKED}.{BLOCKED}.175.29/pdf.php

Download Routine

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

  • Adobe Reader And Acrobat util.printf Stack Buffer Overflow
  • Adobe TIFF File Vulnerability

After successfully exploiting the said vulnerability, this malware connects to the following URLs to possibly download other malicious files:

  • http://{BLOCKED} - inaccessible
  • http://{BLOCKED}rg/firefox/l.php?i=8 - inaccessible
  • http://{BLOCKED}.175.29/load.php - detected as TROJ_DNSCHANG.XT
  • http://{BLOCKED} - also detected as TROJ_PIDIEF.AAL
  • http://{BLOCKED}.biz/var/l.php?i=8 - detected as TROJ_FRAUDPAC.QL
  • http://{BLOCKED} - inaccessible
  • http://{BLOCKED} - also detected as TROJ_PIDIEF.AAL

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


Minimum Scan Engine: 8.900
VSAPI OPR PATTERN File: 7.123.00
VSAPI OPR PATTERN Date: 23 Apr 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

Remove malware files dropped/downloaded by TROJ_PIDIEF.AAL

Step 3

Scan your computer with your Trend Micro product to delete files detected as TROJ_PIDIEF.AAL. 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 these security patches Refrain from using these products until the appropriate patches have been installed. Trend Micro advises users to download critical patches upon release by vendors.  

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