Threat description




Trojan:SymbOS/Singlejump.B disables most well-known third party file managers and Anti-Virus software.


Disinfection with two Series 60 phones

For full disinfection of Singlejump.B you need help of another Series 60 phone that is not infected with the trojan, and clean memory card on that phone.

Download F-Skulls tool onto a PC or directly onto a phone:

  • Install F-Skulls.sis into clean phones memory card with a clean phone
  • Put the memory card with F-Skulls into infected phone
  • Start up the infected phone, the application menu should work now
  • Go to application manager and uninstall the SIS file in which you installed the skulls variant
  • Download and install F-Secure Mobile Anti-Virus to remove any Cabirs or with mobile itself
  • Install EFilemanager file manager application on your phone from
  • Insert the infected memory card into the phone and remove the following files:
  • E:\System\Apps\SystemExplorer\
  • E:\System\Apps\smartfileman\
  • E:\System\Apps\file\
  • E:\System\Apps\Anti-Virus\
  • E:\System\Apps\Anti-Virus\
  • E:\System\Apps\AppInst\Appinst.aif
  • E:\System\Apps\AppInst\
  • E:\System\Apps\cabirfix\
  • E:\System\Apps\Decabir\DECABIR.APP
  • E:\System\Apps\Disinfect\
  • E:\System\Apps\FExplorer\

Technical Details

Trojan:SymbOS/Singlejump.B is distributed in a malicious SIS file named 'Metal_gear.sis'.

Singlejump.B was formerly named Trojan:SymbOS/Onehop.B, but was renamed to Singlejump.B for more accurate classification.


When executed, the trojan disables most well known third party file managers and Anti-Virus software. Singlejump.B tries to disable F-Secure Mobile Anti-Virus by replacing its files with non-functional versions.

It also installs Bluetooth-Worm:SymbOS/Cabir.G on the phone.

Singlejump.B disables the following applications

  • Simworks Anti-Virus
  • F-Secure Mobile Anti-Virus
  • Application installer
  • Cabirfix
  • Decabir
  • F-Cabir
  • FExplorer
  • File manager
  • Smart file manager
  • System Explorer

F-Secure Mobile Anti-Virus is capable of detecting Cabir.G contained by Singlejump.B using generic detection. The Anti-Virus will detect the infected SIS file and prevent it from being installed.

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