While Facebook flip-flops over whether or not its track-after-logout cookies were or were not benign, the Office of the Australian Information Commissioner is reportedly taking a look at whether or not the cookies breached privacy laws.
Facebook initially denied that there was any problem with its cookies, telling blogger Nic Cubrilovic in a blog post that the cookies stored only benign information. However, Cubrilovic yesterday told The Australian that in a conference call, Facebook promised a “fix within 24 hours”.
Following Facebook’s first response to his concerns, Cubrilovic posted a table which further detailed cookie behaviour. These include cookies that are preserved with their original values intact after logout, one which on logout has its expiry reset to 2013, and four cookies that are added upon logout.
He has now posted that the fix has now been implemented, with the most important cookie, a_user, now destroyed on logout.
The promise to revise the cookies so that they don’t contain “personally identifiable information” appears to contradict the
data harvester’s social network’s earlier assertion that users have nothing to worry about.
The Register has offered Facebook the opportunity to comment – twice – but has yet to receive a response. ®
Update: The Register has heard back from Facebook. Although the cookies behaved as documented by Cubrilovic, the company says it did not collect or use the cookies' information. Here is the meat of its response:
Nik Cubrilovic provided us with additional information that allowed us to identify three cookies on some users' computers that 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. Even though we weren't using this information, it's important to us that we address even potential issues, and we appreciate that Nik Cubrilovic brought it to our attention.
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 thapersonalizes content and tries to provide a secure experience for users, we place cookies on the computer of the user.
When Nik provided us with the additional information that allowed is to identify these three cookies, we moved quickly to fix the cookies so that they won't include unique information in the future when people log out.
As you can appreciate,we value the security community and their willingness to provide feedback on issues that they identify. This is why we established our Whitehat program (http://www.facebook.com/whitehat) to provide a direct line of communication to this community. Since then, we've also established a Bug Bounty program that provides financial incentives and rewards for researchers to report potential security issues (http://www.facebook.com/notes/facebook-security/updates-to-the-bug-bounty-program/10150270651335766). ®