New Trojan can knock out Symbian phones

Users of Symbian Series 60 smart phones should be aware of a new Trojan horse that, if not removed within one hour, can cause complete data loss in their wireless devices, security experts warned.

Several owners of Symbian-based handsets have caught the Trojan Doomboot.A. after downloading unauthorized mobile phone games containing the malware, said Anton Von Troyer, marketing manager of Finnish antivirus vendor F-Secure.

F-Secure warned users on Friday on its Web site that Doomboot.A was in the wild.

Von Troyer estimated that around 30 million phones are potentially threatened.

What makes Doomboot.A a serious threat to phones, according to Von Troyer, is the Commwarrior.B worm it contains.

The worm propagates itself by sending a steady flow of messages via the Multimedia Messaging Service (MMS) and short-range Bluetooth, both of which are fairly standard features in smart phones.

"The worm sends a continuous stream of MMS messages, which will drain the battery of most phones in about an hour," Von Troyer said. "When users try to reboot, they can't. Their handsets needs to be reformatted, resulting in complete loss of their data, such as photos, calendar and address book."

Most users wouldn't notice if their phones had been infected, according to Von Troyer. No icons appear; the only indication is a rapid drain of the battery.

Users who detect the Trojan have about an hour to open the application manager program in their phone and remove the malware before the battery drains.

"We're suggesting that people use common sense when going to Web sites and downloading unauthorized Symbian-based mobile phone games," Von Troyer said. "And we're also recommending that they use antivirus programs to protect their devices from viruses, Trojan horses and worms."