Cardtrap.B is a minor variation of Cardtrap.A, the main differences are
that Cardtrap.B drops corrupted binaries from Doomboot.A and copies one
additional copy of Win32/Padobot.Z to memory card.
The Cardtrap.B installs Windows worms Win32/Padobot.Z and Win32/Rays to the
phone memory card.
The Padobot.Z is copied along with autorun file that points to the Padobot.Z
executable, so that if the card is inserted into PC using Windows the autorun
tries to execute Padobot.Z.
We tried this feature with Windows XP SP2 and Windows 2000, and could not get
autorun to work. But the autorun feature might work with some Windows installations.
The Win32/Rays is copied with name System.exe and has the same icon as System folder
in the memory card. So that if user is trying to read the contents of card with PC
he might accidentally execute the Win32/Rays.
Another copy of Padobot.Z is copied to System/Apps directory in with name Apps.exe,
using the same kind of social engineering as Win32/Rays copied to System directory.
Cardtrap.C also drops components from SymbOS/Doomboot.A, which prevent the phone from
booting. So if your phone is infected with Cardtrap.C it is important not to reboot the phone
before disinfecting it.
Disinfection
The Cardtrap.B disables Application manager to prevent it's uninstallation but
it does not prevent installation of Anti-Virus. F-Secure Mobile Anti-Virus can
detect and disinfect the files Cardtrap.B uses to disable the phone.
1. Open web browser on the phone
2. Go to http://mobile.f-secure.com
3. Select link "Download F-Secure Mobile Anti-Virus" and then select phone model
4. Download the file and select open after download
5. Install F-Secure Mobile Anti-Virus
6. Go to applications menu and start Anti-Virus
7. Activate Anti-Virus and scan all files. Anti-Virus then removes files that
block application manager and other critical functions
8. Go to application manager and uninstall the file in which the Cardtrap.B was
installed
When installed Cardtrap.B will replace the main executable of several
third party applications by overwriting their main executable file.
If any third party applications targeted by the trojan are installed
on the device, their main executable will be overwritten, and must be
reinstalled to repair the damage.
Payload
Disables most of the phone built in applications and installs Windows
worms Win32/Padobot.Z and Win32/Rays on the device memory card.
Cardtrap.C also drops components from SymbOS/Doomboot.A, which prevent the phone from
booting.
