Facebook is suing an online pornography business that allegedly hacked into the social network’s computer system to steal its users’ personal details.

Court documents filed by Facebook in San Jose, California, claim that its servers were targeted 200,000 times during a two-week period in June.

It is alleged the attacks came from Istra Holdings, a Canadian company that controls SlickCash.com, an online business that pays commissions to web publishers who direct users to its portfolio of pornography sites.

According to the court filing, the attacks “sought to direct Facebook’s computers to send information on other Facebook users back to (the defendant’s internet) address.”

Security experts say that Facebook, which claims to have more than 55 million members, has become an established target for gangs that collate personal data — both for targeted ID theft and for broader purposes such as compiling addresses for spam e-mail campaigns.

Mike Haro, of Sophos, a security firm, said: “Big populations mean lots of information to steal.”

It is unclear whether data was actually stolen from Facebook, which declined to comment. Istra Holdings did not respond to calls.

Facebook, like other social network sites, solicits and stores information on its users, ranging from their dates of birth and e-mail addresses to their religious and political views.

The Information Commissioner’s Office (ICO), the body responsible for policing the UK’s data protection laws, recently gave warning that millions of Britons are disclosing inappropriate information on social networks.

It called for the public to “wise up” to the potential risks of identity theft.

Privacy concerns could distract Facebook as it strives to reap profits from its vast user base.

The three-year-old site recently achieved an implied valuation of $15 billion (£7.2billion) after Microsoft took a minority stake but is expected to post a profit of only $30 million this year.

This month the site apologised to its users for publicising details of their shopping habits without their permission.

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