Embarrassing privacy flaw found on Facebook

Graham Cluley
@gcluley

A researcher has found a critical security flaw on Facebook that could be exploited by hackers to expose sensitive information about users.

M J Keith, a senior security analyst with security firm Alert Logic, discovered the vulnerability which could lead to private information being exposed, or users’ Facebook pages being maliciously defaced.

IDG security reporter Robert McMillan has explained the problem well:

The bug has to do with the way that Facebook checked to make sure that browsers connecting with the site were the ones they claimed to be. Facebook’s servers use code called a “post_form_id” token to check that the browser trying to do something — liking a group, for example — was actually the browser that had logged into the account. Facebook’s servers check this token before making any changes to…

Read more in my article on the Naked Security website.

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Graham Cluley is a veteran of the anti-virus industry having worked for a number of security companies since the early 1990s when he wrote the first ever version of Dr Solomon's Anti-Virus Toolkit for Windows. Now an independent security analyst, he regularly makes media appearances and is an international public speaker on the topic of computer security, hackers, and online privacy. Follow him on Twitter at @gcluley, or drop him an email.