Fake wi-fi 'steals data and numbers from smartphones'
23 November 2010 Last updated at 06:58 GMT
A fake wi-fi hotspot run by criminals could allow them to steal passwords and log into social networking sites.
Tom Beale from security firm Vigilante Bespoke shows the BBC's Rory Cellan-Jones how easily data can be stolen from a smartphone.
Facebook has responded by saying it advises people to be careful with what data they give out to unknown networks, "in the same way we look to draw out cash from legitimate ATM (cashpoint) machines".
It also pointed out that it asks members whether they want to give Facebook access to contacts stored by email providers before downloading such information from other organisations.
Apple has responded to the way that the latest iPhone is unlocked in this video, by saying that a recent update can be downloaded to prevent this.