Risk: Low
Some useful citizen has written a virus which targets mobile phones running the Symbian operating system. Anti-virus groups received the worm from its authors but it is not yet "in the wild".
The Cabir worm is the first network worm for mobile phones, according to Kaspersky Labs. It was written by 29a, a group of virus writers which specialises in proof-of-concept viruses - they made the first viruses for .NET and for Win64.
The virus transfers itself as a .sis (Symbian OS distribution) file but is disguised as a Caribe Security Manager utility. It uses Bluetooth technology to find another Symbian phone and forwards itself on. The worm has no malicious payload but will display the message "Caribe" if launched.
A spokesman for Symbian said: "We take security seriously and are looking at this carefully. But as we understand it at this point this requires the user to have Bluetooth switched on and to say yes to installing an application despite two messages warning that the source of the software is unknown."
Kaspersky warns that the worm could run on other operating systems.