TROJ_STRAT.EL

Malware type: Trojan

Aliases: Email-Worm.Win32.Warezov.do (Kaspersky), W32/Stration@MM (McAfee), W32.Stration@mm (Symantec), Worm/Stration.BL.3 (Avira),

In the wild: Yes

Destructive: No

Language: English

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

Encrypted: No

Overall risk rating:

Reported infections:

Damage potential:

Medium

Distribution potential:

Low

Description: 

On September 22, 2006, in the face of increasing infections and seemingly endless release of new variants into the wild, the Trend Micro Japan office declared a local alert to control the onslaught of WORM_STRATION, which was quickly gaining the notoriety for spawning iterations in rates not seen since 2005's MYTOB. In just a few weeks, WORM_STRATION was also found spreading like wild fire in the rest of the world, primarily in the US. Read an article documenting the STRATION event here: The STRATION Strategy.

This Trojan arrives on a system as a file dropped by other WORM_STRAT variants.

It is installed in the Windows system folder using any of several file names.

This Trojan may download possibly malicious files from certain URLs.

For additional information about this threat, see:

Description created: Oct. 27, 2006 2:25:01 AM GMT -0800


TECHNICAL DETAILS


File type: PE

Memory resident:  Yes

Size of malware: Varies

Initial samples received on: Oct 24, 2006

Payload 1: Downloads files

Details:

This Trojan arrives on a system as a file dropped by other WORM_STRAT variants.

It is installed in the Windows system folder using any of the following file names:

  • D3DPRF32.DLL
  • D3DPROV.EXE
  • DECCONF.EXE
  • DIAGD3D.DLL
  • STATD3D.DLL

It creates the following registry entry to ensure its automatic execution at every Windows startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Ciodiag = "%System%\DECCONF.EXE"

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It also modifies the following registry entry as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Windows
AppInit_DLLs = "diagd3d.dll statd3d.dll"

(Note: The default value data for the abovementioned registry entry is "".)

This Trojan may download possibly malicious files from certain URLs.

It runs on Windows 98, ME, NT, 2000, XP, and Server 2003.

Analysis By: Alvin Jethro Calderon Bacani

Revision History:

First pattern file version: 3.876.04
First pattern file release date: Oct 24, 2006

SOLUTION


Minimum scan engine version needed: 8.000

Pattern file needed: 5.541.00

Pattern release date: Sep 14, 2008


Important note: The "Minimum scan engine" refers to the earliest Trend Micro scan engine version guaranteed to detect this threat. However, Trend Micro strongly recommends that you update to the latest version in order to get comprehensive protection. Download the latest scan engine here.

Solution:

Identifying the Malware Program

To remove this malware, first identify the malware program.

  1. Scan your computer with your Trend Micro antivirus product.
  2. NOTE the path and file name of all files detected as TROJ_STRAT.EL.

Trend Micro customers need to download the latest virus pattern file before scanning their computer. Other users can use Housecall, the Trend Micro online virus scanner.

Restarting in Safe Mode

This malware has characteristics that require the computer to be restarted in safe mode. Go to this page for instructions on how to restart your computer in safe mode.

Editing the Registry

This malware modifies the computer's registry. Users affected by this malware may need to modify or delete specific registry keys or entries. For detailed information regarding registry editing, please refer to the following articles from Microsoft:

  1. HOW TO: Backup, Edit, and Restore the Registry in Windows 95, Windows 98, and Windows ME
  2. HOW TO: Backup, Edit, and Restore the Registry in Windows NT 4.0
  3. HOW TO: Backup, Edit, and Restore the Registry in Windows 2000
  4. HOW TO: Back Up, Edit, and Restore the Registry in Windows XP and Server 2003

Removing Autostart Entries from the Registry

Removing autostart entries from the registry prevents the malware from executing at startup.

If the registry entries below are not found, the malware may not have executed as of detection. If so, proceed to the succeeding solution set.

  1. Open Registry Editor. Click Start>Run, type REGEDIT, then press Enter.
  2. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>
    Windows>CurrentVersion>Run
  3. In the right panel, locate and delete the entry:
    Ciodiag = "%System%\DECCONF.EXE"
    (Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, and C:\Windows\System32 on Windows XP and Server 2003.)

Restoring Modified Entry in the Registry

  1. Still in Registry Editor, in the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft> Windows NT>CurrentVersion>Windows
  2. In the right panel, locate the entry:
    AppInit_DLLs = "diagd3d.dll statd3d.dll"
  3. Right-click on this entry and choose Modify. Change the value of this entry to:
    AppInit_DLLs = ""
  4. Close Registry Editor.

Important Windows ME/XP Cleaning Instructions

Users running Windows ME and XP must disable System Restore to allow full scanning of infected computers.

Users running other Windows versions can proceed with the succeeding solution set(s).

Running Trend Micro Antivirus

If you are currently running in safe mode, please restart your computer normally before performing the following solution.

Scan your computer with Trend Micro antivirus and delete files detected as TROJ_STRAT.EL. To do this, Trend Micro customers must download the latest virus pattern file and scan their computer. Other Internet users can use HouseCall, the Trend Micro online virus scanner.




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