Several Trojan horses that target mobile phones have been discovered since the start of the year, but the threat level remains low.
Symantec, which sells software to protect mobile devices, has since the beginning of the month identified nine new Trojan horses that target the Symbian operating system. The pests crash phones, attempt to install other malicious software or try to wirelessly transmit personal data to other gadgets, according to Symantec.
Symbian OS is the most popular operating system for smartphones, including those sold by market leader Nokia. Two-thirds of all smartphones shipped in the third quarter of last year ran the Symbian OS, according to recent Gartner research.
In October of last year, Nokia signed a deal with Symantec to arm its Series 60 smartphones with the Symantec Mobile Security antivirus program. F-Secure and McAfee are among the other vendors of antivirus products for mobile phones.
All of the new pests propagate via Bluetooth, the short-range wireless technology used in many mobile phones. Since 1 January, Symantec has identified five variants of "Cdropper", two versions of "Pbstealer", and one each of "Sendtool" and "Booton", according to its DeepSight alerts service. The latest pests were discovered this week.
Pbstealer tries to send the user's address book, notepad content, calendar and task list to other Bluetooth devices while Cdropper attempts to install versions of the Cabir and Locknut viruses on the mobile device, according to Symantec.
Booton can perhaps wreak the most havoc. It restarts the mobile device when executed, but the restart will fail because the Trojan also drops corrupted files on the system, Symantec said. Sendtool drops a tool that can be used to send malicious programs, such as other Trojans, to other Bluetooth-enabled devices.
While the number of threats may appear high, the actual threat level is low. Symantec has seen very few, if any, reported infections. Most of the Trojan horses require a user to execute a file received via Bluetooth and acknowledge a warning from the system that the file may be from an untrusted source and cause problems, Symantec said.
Some antivirus experts, however, have predicted that mobile phone pests will become an increasing problem.
In the third quarter of 2005, worldwide shipments of smartphones totalled 12.6m units, up 210 percent year-on-year, according to Gartner. As a proportion of all mobile shipments, smartphone shipments increased to 6.1 percent from 2.4 percent in last year's period, Gartner said.
