Analysis by: Karl Dominguez
 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: Yes

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

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

  TECHNICAL DETAILS

File Size: Varies
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 18 Oct 2010

Arrival Details

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

Installation

This Trojan drops and executes the following files:

  • %User Temp%\{random characters}\Stuxnet Cleaner.bat

(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.)

Other System Modifications

This Trojan deletes the following files:

  • All files in the C:\ drive

It modifies the following registry entries:

HKEY_CLASSES_ROOT\.bmp
(Default) = THEMEFile

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

HKEY_CLASSES_ROOT\.exe
(Default) = WMAFile

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

HKEY_CLASSES_ROOT\.gif
(Default) = THEMEFile

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

HKEY_CLASSES_ROOT\.jpg
(Default) = THEMEFile

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

HKEY_CLASSES_ROOT\.mp3
(Default) = VBSFile

(Note: The default value data of the said registry entry is mp3file.)

Process Termination

This Trojan terminates processes or services that contain any of the following strings if found running in the affected system's memory:

  • explorer.exe
  • firefox.exe
  • iexplore.exe
  • avgnt.exe

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: 7.550.09
FIRST VSAPI PATTERN DATE: 18 Oct 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

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_CLASSES_ROOT\.bmp
    • From: (Default) = THEMEFile
      To: (Default) = Paint.Picture
  • In HKEY_CLASSES_ROOT\.exe
    • From: (Default) = WMAFile
      To: (Default) = exefile
  • In HKEY_CLASSES_ROOT\.gif
    • From: (Default) = THEMEFile
      To: (Default) = giffile
  • In HKEY_CLASSES_ROOT\.jpg
    • From: (Default) = THEMEFile
      To: (Default) = jpegfile
  • In HKEY_CLASSES_ROOT\.mp3
    • From: (Default) = VBSFile
      To: (Default) = mp3file

Step 3

Search and delete these files

[ Learn More ]
There may be some component files 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. %User Temp%\{random characters}\Stuxnet Cleaner.bat

Step 4

Restore files from backup Only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on your computer again.

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_BATTOEXE.C. 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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