Singlejump.J (renamed Onehop.J) is Symbian SIS file trojan that replaces system files and some 3rd party applications with corrupted binaries from SymbOS/Doomboot.A trojan. These components prevent phone from rebooting, so if your phone is infected with Singlejump.J, it is critical not to reboot the phone.

Singlejump.J sends also SymbOS/Onehop.B to the first device it finds with Bluetooth.


Disinfection with two Series 60 phones

Download F-Skulls tool from our FTP server to your computer or to a clean phone, then:

  • Install F-Skulls.sis into infected 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
  • Press menu button until you get Symbian process menu, look for any applications with strange icons. Kill the application processes with 'C' button.
  • Go to application manager and uninstall the SIS file in which you installed the Singlejump.J
  • Download F-Secure Mobile Security and activate it
  • Scan the phone and remove any remaining components of Singlejump.J
  • Remove the F-Skulls with application manager as the phone is now cleaned

Disinfection for the cases when phone is already rebooted and cannot start up

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

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

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User Guide

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Submit a sample

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Technical Details

Spreading in: SC-PT_carcked_Ngage_DFT.sis


Singlejump.J replaces built in and third party applications with component that causes reboot to fail.

Singlejump.J use modified Cabir to spread other trojans. Instead of sending a copy of itself it loads SIS file installed by Singlejump.J and sends it to the first phone it finds within Bluetooth range.

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