Personal details of Facebook users could potentially be stolen, the BBC technology programme Click has found.
The popular social networking site allows users to add a variety of applications to their profile.
But a malicious program, masquerading as a harmless application, could potentially harvest personal data.
We have discovered a way to steal the personal details of you and all your Facebook friends without you knowing.
We wrote an evil data mining application called Miner, which, if we wanted, could masquerade as a game, a test, or a joke of the day. It took us less than three hours.
But whatever it looks like, in the background, it is collecting personal details, and those of the users' friends, and e-mailing them out of Facebook, to our inbox.
When you add an application, unless you say otherwise, it is given access to most of the information in your profile. That includes information you have on your friends even if they think they have tight security settings.
It certainly seems that Facebook's standard security settings are not sufficient to protect your personal information, and those of your friends.