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Category: Malware

Type: Trojan

Platform: SymbOS

Aliases: SymbOS/AppDisabler, Trojan:SymbOS/AppDisabler, SymbOS/AppDisabler


Trojan:SymbOS/AppDisabler is a family of malicious SIS file trojans, which attempt to disable a number of Symbian OS system and third party applications.


Disinfection with two Series 60 phones

To perform this disinfection routine, use the F-Skulls utility tool to allow installation of F-Secure Mobile Anti-Virus, then install F-Secure Mobile Anti-Virus to remove the infection.

Download F-Skulls tool from ftp://ftp.f-secure.com/anti-virus/tools/f-skulls.zip or directly to a clean phone from https://www.f-secure.com/tools/f-skulls.sis.

  • 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
Disinfection for the cases when phone cannot start up

CAUTION This method will remove all data on the device, including calendar and phone numbers

  • Power off the phone
  • Hold the following three buttons down - "answer call" + "*" + "3"
  • Keep holding down the buttons and power on the phone
  • Depending on the model, you will either get text that reads "formatting" or a start-up dialog that asks for the initial phone settings
  • Your phone is now formatted and can be used again
Knowledge Base

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About the product

See the manual for your F-Secure product on the Help Center.

Contact Support

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Submit a sample

Submit a file or URL for further analysis.

Technical Details

In addition to disabling applications, some AppDisabler variants replace the phone operator logo and background image. Other variants will drop additional malware on the system.

Some Appdisabler variants are nonfunctional; due to a bug or implementation error, they do not run as intended.


When installing itself AppDisabler replaces the main executable of several system and third party applications by overwriting their main executable file. These files must be reinstalled to repair the damage.


Listed below are some representative examples of Appdisabler variants:

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