Threat description


Type: Trojan
Platform: SymbOS
Aliases: SDropper


This family of trojans drops files from the SymbOS/Skulls family. Members of the SDropper family have no additional interesting functionality apart from dropping and installing an embedded Skulls SIS file along with some additional non-malware software.


Please see the instructions below for F-Secure's F-Skulls tool. The tool will help in removing the Skulls files that were dropped by the member of the SDropper family.

Disinfection with two Series 60 phones

Use F-Skulls to allow for installation of F-Secure Mobile Anti-Virus

Download F-Skulls tool from or directly to a clean phone from

Install F-Secure Mobile Anti-Virus

  • Install F-Skulls.sis onto the infected phone's memory card with a clean phone
  • Put the memory card with the F-Skulls tool into the infected phone
  • Start up the infected phone and the application installer should now work
  • Go to the application manager and uninstall the SIS file in which you installed the malware
  • Download F-Secure Mobile Security and activate it
  • Scan the phone and remove any remaining components of the malware
  • Remove the F-Skulls tool with the application manager as the phone should now be clean

Description Details: Juha-Pekka Heikkila, March 24, 2006
Technical Details:Juha-Pekka Heikkila, March 24, 2006


Suspect a file or URL was wrongly detected? Submit a sample to our Labs for analysis

Submit Now

Protect your life on every device

F-Secure SAFE looks out for you and the people close to you, on every device, all the time.

Learn More