Analysis by: jasperm
 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This backdoor may be dropped by other malware. It may be unknowingly downloaded by a user while visiting malicious websites.

It connects to Internet Relay Chat (IRC) servers. It opens a random port to allow a remote user to connect to the affected system. Once a successful connection is established, the remote user executes commands on the affected system. It connects to a website to send and receive information.

  TECHNICAL DETAILS

File Size: 98,304 bytes
File Type: PE
Memory Resident: Yes
Initial Samples Received Date: 10 Feb 2010

Arrival Details

This backdoor may be dropped by other malware.

It may be unknowingly downloaded by a user while visiting malicious websites.

Installation

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

  • %Program Files%\Common Files\System\taskmger.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)

Autostart Technique

This backdoor adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
Windows Update = %Program Files%\Common Files\System\taskmger.exe

Other System Modifications

This backdoor creates the following registry entry(ies) to bypass Windows Firewall:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%Program Files%\\Common Files\\System\\taskmger.exe = %Program Files%\Common Files\System\taskmger.exe:*:Enabled:Windows Update

Backdoor Routine

This backdoor connects to any of the following Internet Relay Chat (IRC) servers:

  • fo3.net

It joins any of the following IRC channel(s):

  • #Huxor#
  • #huxor.scan#
  • #Huxor.scan#
  • #log#

It opens a random port to allow a remote user to connect to the affected system. Once a successful connection is established, the remote user executes commands on the affected system.

It connects to the following websites to send and receive information:

  • {BLOCKED}r.psybnc.cz

  SOLUTION

Minimum Scan Engine: 8.900

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

Identify and terminate files detected as BKDR_PINCAV.AO

[ Learn More ]
  1. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  2. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 3

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    • Windows Update=%Program Files%\Common Files\System\taskmger.exe

Step 4

Scan your computer with your Trend Micro product to delete files detected as BKDR_PINCAV.AO. 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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