TROJ_DROPPER.IJX

 Analysis by: Marfel Tiamzon

 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW


This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File Size:

580830 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

19 Jan 2011

Payload:

Drops files

Arrival Details

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This Trojan drops the following files:

  • %WINDOWS%\services.exe - detected as WORM_AUTORUN.FJI
  • %WINDOWS%\oodbnt2.ini
  • %WINDOWS%\UNINSTALLC32.exe - detected as TROJ_FALERT.MCS
  • %WINDOWS%\LastGood\system32\scrrun.dll
  • %system%\dllcache\scrrun.dll
  • %USER TEMP%\errdlg.exe
  • %USER TEMP%\rememberthistime.rar
  • %USER TEMP%\Videoman1.exe
  • %USER TEMP%\Videoman2.exe

It drops the following copies of itself into the affected system:

  • %WINDOWS%\Pifex32.inf

It creates the following folders:

  • %WINDOWS%\LastGood
  • %WINDOWS%\LastGood\system32
  • %Program Files%\Programs

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

Other System Modifications

This Trojan also creates the following registry entry(ies) as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Programs.exe\
Programs
Directory = %Program Files%\Programs

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\SharedDLLs
%system%\scrrun.dll = 1

  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

Delete this registry key

[ 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\Programs.exe

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\SharedDLLs
    • %system%\scrrun.dll = 1

Step 4

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.
  • In %WINDOWS%\oodbnt2.ini
    • %system%\dllcache\scrrun.dll
      • %USER TEMP%\errdlg.exe
        • %USER TEMP%\rememberthistime.rar
          • %USER TEMP%\Videoman1.exe
            • %USER TEMP%\Videoman2.exe

Step 5

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • In %WINDOWS%\LastGood
    • %Program Files%\Programs

Step 6

Remove malware files dropped/downloaded by TROJ_DROPPER.IJX

    • In TROJ_FALERT.MCS
      • WORM_AUTORUN.FJI

Step 7

Scan your computer with your Trend Micro product to delete files detected as TROJ_DROPPER.IJX. 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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