Jarno Niemela of F-Secure in Finland has identified Cardtrap.A, a malicious SIS file trojan that tries to disable large number of system and third party applications and installs Windows malware on the phone memory card of Symbian OS smartphones.

Cardtrap.A installs Windows worms Win32/Padobot.Z and Win32/Rays to the phone memory card. The Padobot.Z is copied along with an 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," noted Niemala, "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 a PC," Niemala added, "he might accidentally execute the Win32/Rays."