Phone-mad Finns are coping with a minor outbreak of the Cabir mobile virus at the Athletic's World Championship in Helsinki this week. Cabir, which infects smartphones running Symbian Series 60 using Bluetooth short-range radio communication technology to spread, is flourishing in the packed stadium area. The version of Cabir spreading drains the power of the infected phones as it tries to propagate but is otherwise relatively harmless.

"At most we are speaking about dozens of infections, but during a short period and in one spot this is a huge number," Jarmo Koski, a security official at telecoms firm TeliaSonera, told Reuters.

Prospective victims need to accept a download to get hit by Cabir and security researchers reckon many handsets get infected simply because users get fed up with being prompted to allow a connection. Moving away from an infected phone is an effective defence if a malign connection is attempted in, for example, a bar but is harder to apply when you're in a crowded stadium where perhaps the best approach is to turn off Bluetooth on potentially vulnerable phones.

"This [Cabir spreading] happens easily when you gather tens of thousands of people from all over to world to a very small area. In fact, to some extent the same thing was happening during the Live 8 concerts earlier this summer," said Mikko Hyppönen, director of anti-virus research at Finnish anti-virus firm F-Secure, in a posting on the firm's blog. "We now have staff at the stadium assisting visitors in cleaning out affected phones." ®