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TROJ_DROPR.SM2

October 09, 2012
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • 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.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

03 May 2012

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.

Other Details

This Trojan deletes itself after execution.

NOTES:

This Trojan overwrites the following legitimate Windows file:

  • %System%\ws2help.dll - detected as TSPY_ONLINEG.SM3

The original copy is saved as %System%\ws2helpXP.DLL.

It then executes the dropped file. As a result, malicious routines of the dropped file are exhibited on the affected system.

This malware modifies the following registry entry as an autostart for its dropped malware:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Windows
AppInit_Dlls = "ws2help.dll"
(Original Value is AppInit_Dlls="")

  SOLUTION

Minimum Scan Engine:

9.200

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

Remove malware/grayware files dropped/downloaded by TROJ_DROPR.SM2

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 = "ws2help.dll"
      To: AppInit_Dlls = ""
RESTORE
  • Close Registry Editor.

    • Step 4

    Scan your computer with your Trend Micro product to delete files detected as TROJ_DROPR.SM2. 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.

    Step 5

    Restore these deleted files from backup

    *Note: Only Microsoft-related keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

    %System%\ws2help.dll


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