Skulls.J is minor variant of Skulls.D trojan. The main difference
between Skulls.J and Skulls.D is that the Skulls.J doesn't drop
any cabir variants directly. The Skulls.J drops SymbOS/AppDisabler.A trojan,
which drops Cabir.Y and Locknut.B on the device.
In addition of dropping the AppDisabler.A the Skulls.J tries to disable
F-Secure Anti-Virus and other Anti-Virus applications.
F-Secure Anti-Virus protected from the trojan attack as it is capable
of detecting the trojan using generic detection, which was created long
before this trojan surfaced.
Spreading in
Skulls.J trojan SIS file has been manually inserted into several different
pirate copied games and applications. However none of these files have
been detected in the wild.
Payload
Tries to disable Anti-Virus and drops SymbOS/Appdisabler.A.
Skulls.J also contains application that displays animation of flashing skull
picture. But unlike in Skulls.D, Skulls.J does not contain startup code for
the animation, this code is introduced by AppDisabler.A, but is prevented
from working by Locknut.B which is also dropped by Appdisabler.A.
