Facebook has said that it has "fixed" cookies that could have tracked the websites users visited even after logging out of the social networking site.
Australian hacker and blogger Nik Cubrilovic had been trying to get the company’s attention over the glitch for almost a year.
Last week, Cubrilovic posted details of the cookies on his blog, showing that logging out of Facebook’s site was not truly looging out for its over 750 million users worldwide.
Cubrilovic conducted a year-long analysis of the social network’s use of cookies before blogging about the glitch.
Cubrilovic had discovered last year that cookies dropped by Facebook during a session, remained and collected data of other Facebook linked websites. He wrote to the social networking site instead of making the matter public. But Cubrilovic’s mails were all ignored, the hacker claimed.
Frustration over lack of response made him to post details on his blog.
Cubrilovic wrote on his blog: "To clarify, I first emailed this issue to Facebook on the 14th of November 2010. I also copied the email to their press address to get an official response on it. I never got any response. I sent another email to Facebook, press and copied it to somebody I know at Facebook on the 12th of January 2011. Again, I got no response. I have copies of all the emails, the subject lines were very clear in terms of the importance of this issue."
"I have been sitting on this for almost a year now. The renewed discussion about Facebook and privacy this weekend prompted me to write this post."
Cubrilovic’s blog over stealth Facebook cookies raised privacy concerns about the service. The Australian privacy commissioner is reportedly investigating the issue, said the BBC.
Earlier this week, Cubrilovic said that he spoke with Facebook engineers, who assured him that the glitch would be fixed in 24 hours.
"They aim to fix it (the logout issue) by tomorrow," Cubrilovic said.
"There will still be cookies, but they won’t be identifiable. That’s within 24 hours.
"We can only take them at their word."
Now, facebook claims that it has fixed the glitch. The company has thanked Cubrilovic. However, it quickly added that the social networking service had done nothing wrong.
Facebook told the BBC, "There was no security or privacy breach — Facebook did not store or use any information it should not have. Like every site on the internet that personalises content and tries to provide a secure experience for users, we place cookies on the computer of the user."
"Three of these cookies on some users’ computers inadvertently included unique identifiers when the user had logged out of Facebook. However, we did not store these identifiers for logged out users. Therefore, we could not have used this information for tracking or any other purpose. In addition, we fixed the cookies so that they won’t include unique information in the future when people log out," said the company.
