Threat description


Platform: W32


Skulls.U is a SIS file trojan that pretends to be installation file for Battery Extender software.


Disinfection with two Series 60 phones

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

  • 1. Install F-Skulls.sis into infected phones memory card with a clean phone
  • 2. Put the memory card with F-Skulls into infected phone
  • 3. The F-Skulls starts automatically upon insertion and frees menu and application manager
  • 4. Go to application manager and uninstall the SIS file in which you installed the Skulls.U
  • 5. Download and install F-Secure Mobile Security on your computer to remove other malware dropped by the Skulls.U, or directly onto the mobile itself
  • 6. Remove the F-Skulls with application manager as the phone is now cleaned

Technical Details

Spreading in: Ximplyfy Battery Extender.sis

When installed Skulls.U disables several built in applications, drops component files from Locknut.A, Doomboot.A and installs Cabir.B and Cabir.X

In addition of directly installing damaging files, Skulls.U also drops Locknut.C and MGDropper.A into the device.

Skulls.U also installs a pirate copied version of Simworks Anti-Virus into the device.


Generic detection that detects Skulls.U was published for F-Secure Mobile Anti-Virus on December 13th, 2004 in Detection Type:Mobile
Database:database build number 15

Description Details: Jarno Niemela November 14th, 2005;


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