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


  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes


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


File Size: Varies
Memory Resident: Yes
Initial Samples Received Date: 12 Jun 2010
Payload: Downloads files

Arrival Details

This Trojan may be downloaded by the following malware/grayware from remote sites:


It may be unknowingly downloaded by a user while visiting the following malicious websites:



This Trojan drops the following component file(s):

  • %User Profile%\Microsoft\smx4pnp.dll

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

smx4pnp = rundll32.exe "%User Profile%\Microsoft\smx4pnp.dll", Launch

Download Routine

This Trojan accesses the following websites to download files:



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

Remove malware files dropped/downloaded by TROJ_SMALL.NSZ

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Search and delete this file

[ 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 Profile%\Microsoft\smx4pnp.dll

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_SMALL.NSZ. 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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