Analysis by: Christopher Daniel So
 Modified by: Michael Cabel
 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This backdoor connects to a website to send and receive information.

  TECHNICAL DETAILS

Ports: TCP Port 80 (HTTP)
File Size: 471,552 bytes
File Type: PE
Memory Resident: No
Initial Samples Received Date: 08 Nov 2010

Installation

This backdoor drops the following copies of itself into the affected system:

  • %User Temp%\is799009782\AInstaller.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.)

Backdoor Routine

This backdoor connects to the following websites to send and receive information:

  • cv.{BLOCKED}er.org
  • usdnld.{BLOCKED}ta.com

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 7.602.08
FIRST VSAPI PATTERN DATE: 08 Nov 2010
VSAPI OPR PATTERN File: 7.603.00
VSAPI OPR PATTERN Date: 08 Nov 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

Scan your computer with your Trend Micro product to delete files detected as BKDR_DELF.PRC. 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.


Did this description help? Tell us how we did.