Described as a virus by some antivirus companies, Commwarrior takes aim at the version of the Symbian operating system running on Nokia Series 60 handsets. It attempts to spread by sending messages via Bluetooth and MMS, which is different from the Cabir virus, which only used Bluetooth to proliferate.
According to Jarno Niemela on antivirus firm F-Secure's web site, the virus is not spreading very much because it can only infect one type of operating system and is not very efficient.
"We have confirmation that Commwarrior is spreading over MMS but there seems to be a significant delay between the MMS messages. As a result, Comwarrior will not spread rapidly like e-mail worms do," said Niemela.
Compared to an e-mail virus, Commwarrior is also relatively difficult to catch, Niemela said.
"Installing application from MMS message takes even more steps than with a bluetooth message. That receiver also has to have compatible phone for the worm to function. As a result Comwarrior MMS spreading is not as dangerous as it could have been," said Niemela.
Another reason Commwarrior is not causing many problems is that the MMS service is not used by all mobile phone users.
"In addition, many operators do not have MMS service enabled for all customers by default, so quite large number of the phones that could be infected cannot send MMS messages. Comwarrior will not cause a massive MMS outbreak, and this is not the end of the world as we know it," added Niemela.
Adam Biviano, senior systems engineer at Trend Micro, agrees that Commwarrior is not spreading as fast as it could do because of its "limited in its target audience."
However, Biviano is concerned that the virus may hold a nasty surprise for infected users because they could face a bill at the end of the month for unknowingly sending out so many MMS messages.
"Mobile companies in Australia are charging their customers by the kilobyte - so Commwarrior could represent a cost to the user that sends it and the receiver. So people could receive a bill at the end of the month that they weren't expecting," said Biviano.
Biviano also warned that future variants of the virus could be modified to behave like a premium rate phone dialler, which is malware that changes the connections settings of a dial-up internet account to call a premium rate number in order to run up huge telephone bills.