A number of media organisations have published stories about a bug in certain Siemens mobile phones which can cause the phones to "freeze" upon receipt of certain text messages. Sophos experts advise customers that this is not the same as a virus, and that a patch is available for protection.
A bug found in the 35 and 45 series of Siemens phones can cause the phones to stop working properly if a carefully constructed EMS (enhanced messaging service) message is sent to the phone. EMS is a technology that allows mobile phones to receive symbols (such as love hearts) as well as traditional text messages.
According to Michael Stenberg, a Siemens spokesperson, the bug allows a message to tell the mobile phone to try and display a symbol which does not exist. The search for the non-existent symbol then freezes the phone.
"This is quite different from a virus," said Graham Cluley, senior technology consultant for Sophos Anti-Virus. "Unlike a virus the text message cannot replicate itself, and has to be deliberately sent to you by someone who knows what make of mobile phone you own. It's pretty unlikely anyone will be hit by this, but if they are all they need to do is briefly switch their mobile phone off to reset it."
Siemens has published a software update on their website which reportedly fixes the bug.