Threat description


Type: Trojan
Platform: SymbOS


Singlejump.C (renamed Onehop.C) is a malicious SIS file dropper, that disables most well known third party file managers and Anti-Virus software. It uses modified Cabir to send itself forward and drops Singlejump.B torjan.

The modified Cabir is started automatically when the Singlejump.C is installed and will start spreading. When spreading from infected phone, the SIS files it sends will contain only the Singlejump.B.

Singlejump.C tries to disable F-Secure Mobile Anti-Virus by replacing it's files with non-functional versions. However as F-Secure Mobile Anti-Virus is capable of detecting Singlejump.C by using generic detection. The Anti-Virus will detect the infected SIS file and prevent it from being installed. Provided that the Anti-Virus is in realtime scan mode as it is by default.


Disinfection with two Series 60 phones

For full disinfection of Singlejump.C 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 from or directly with 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 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

Installation to system

When installed Singlejump.C will replace most common third party file managers, Anti-Virus programs and application installer with non-functional versions.

Spreading in:MetalGear_by_scar69.sis


Disables 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 for Symbian detects this malware starting from the Detection Type:Mobile
Database:update build number 15

Description Details: Jarno Niemela June 15th, 2005
Description Last Modified: Mika Tolvanen, February 15, 2006


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