Yes, cell phones and smart phones are vulnerable to viruses, and phones using the Symbian SymbOS operating system are often targeted. Because the smartphone and cellphone industry uses so many different operating systems, mobile phone viruses have not spread as extensively as computer viruses.
As with personal computers, phone viruses are spread via applications, attachments, and other downloads. Just like in the PC world, smartphone viruses sometimes disguise themselves as games or security patches. Smartphone viruses also use bluetooth, MMS, and ringtones as methods of transmission and infection. Mobile viruses can piggyback on an MMS attachment, or be disguised as a ringtone. One virus, the Bluetooth-Worm SymbOS/Cabir, is capable of spreading itself to any nearby phone with Bluetooth enabled.
The SymbOS operating system is very common worldwide, but not so common in the U.S. anymore. According to the research firm Gartner, Symbian was installed on 37.6% of smartphones sold worldwide in 2010, but ComScore reported in July 2011 that SymbOS only accounted for 2.3% of smartphones in the United States. SymbOS's popularity may decline further as Nokia transitions away from SymbOS to the Windows 7 platform.
Whatever the most popular phone operating system is, it's likely to find itself the target of viruses and exploit attempts.
Gartner Says Worldwide Mobile Device Sales to End Users Reached 1.6 Billion Units in 2010; Smartphone Sales Grew 72 Percent in 2010
comScore Reports July 2011 U.S. Mobile Subscriber Market Share
Posted 967 day ago