3 Mar 2009, 0010 hrs IST, AGENCIES

Caution! Sharing your personal information on social networking sites might make you susceptible to hackers. Facebook has been targeted by malicious hackers seeking to steal valuable data from members.

The social network site has been hit by five separate security problems in the last seven days, say security experts.

By creating fake messages padded with details of Facebook members the thieves are capitalising on the trust and social links that drive the network, BBC website reported on Monday.

Security firms warn that the popularity of social networking sites makes them a tempting target for hi-tech thieves.

"It's been a pretty bad week for social networking in general," said Rik Ferguson, senior security advisor at Trend Micro. In the last week, said Ferguson, Facebook had been hit by four malicious applications as well as a new variant of the Koobface virus that first targeted members of the social site in December 2008.

The rogue applications on Facebook all try to steal saleable information from the profiles of those who open it up, said Ferguson. One malicious application tried to trick people into adding it by claiming that their friends were having trouble looking at their profile. If the application is added it spams itself to every Facebook friend that a member of the site has.

Ferguson said the way that Facebook is built can make it tricky for members to spot malicious or rogue applications. Ferguson said he expected more sophisticated programs that hid their malicious intent to debut soon on social network sites.