Cardtrap.A transfers two Windows worms when the memory card is inserted into the PC.
"When infecting Symbian phone the Cardtrap.A copies two Windows worms Win32/Padobot.Z and Win32/Rays into the phones memory card," said Jarno Niemela, a virus researcher writing on the company's weblog. "Padobot.Z is copied with autostart.inf file in attempt to start automatically if the card is inserted to PC using windows. Rays is copied with filename System and same icon as system folder."
According to F-Secure the virus is the first of its kind. It attempts to catch out the more experienced user who would link an infected mobile phone to a PC in an attempt to remove the mobile virus. But the virus itself may currently be ineffective.
"To our knowledge no Windows version support autostart from a memory card," said Niemela. "But it still might work with some Windows versions and third party driver combination."
In a year of mobile phone virus firsts SC reported in May Commwarrior, the first mobile phone virus to spread via MMS text messages, had infected 22 countries and was spreading around the globe.