Analysis by: adel
 PLATFORM:

Windows 98, ME, NT, 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 has received attention from independent media sources and/or other security firms.

This backdoor may be downloaded by other malware/grayware/spyware from remote sites. It arrives as a component bundled with malware/grayware packages.

It may be injected into processes running in memory.

It opens a hidden Internet Explorer window.

It connects to certain websites to send and receive information.

  TECHNICAL DETAILS

File Size: 20,992 bytes
File Type: PE
Memory Resident: Yes
Initial Samples Received Date: 02 Nov 2009

Arrival Details

This backdoor may be downloaded by other malware/grayware/spyware from remote sites.

It arrives as a component bundled with malware/grayware packages.

Installation

This backdoor may be injected into processes running in memory.

Autostart Technique

This backdoor modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Windows
AppInit_DLLs = ms32clod.dll

(Note: The default value data of the said registry entry is  .)

Other System Modifications

This backdoor adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\MSControls
s = 1

Backdoor Routine

This backdoor opens a hidden Internet Explorer window.

Download Routine

This backdoor accesses the following websites to download files:

  • http://{BLOCKED}r.cn/l1/ist.dat
  • http://{BLOCKED}r.cn/l1/pst.dat

It connects to the following URL(s) to download its component file(s):

  • http://{BLOCKED}r.cn/l1/ms32clod.dll - also detected as BKDR_CLICKER.EYE

It saves the files it downloads using the following names:

  • %System%\ist.dat
  • %System%\pst.dat

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Other Details

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

  • http://{BLOCKED}r.cn

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: 6.602.01
FIRST VSAPI PATTERN DATE: 03 Nov 2009
VSAPI OPR PATTERN File: 6.603.00
VSAPI OPR PATTERN Date: 03 Nov 2009

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

Restore this modified 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 NT\CurrentVersion\Windows
    • From: AppInit_DLLs = ms32clod.dll
      To: AppInit_DLLs =  

Step 4

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\MSControls
    • s = 1

Step 5

Search and delete these components

[ Learn More ]
There may be some components that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %System%\ist.dat
  • %System%\pst.dat

Step 6

Scan your computer with your Trend Micro product to delete files detected as BKDR_CLICKER.EYE. 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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