Users of Hulu and MSN, among others, may have fallen victim to a new wave of powerful cookies collecting their personal data. That's according to a new report publicised by the Wall Street Journal, which claims such websites are leaving cookies that persist even after the user has "cleared" their cookies. The "supercookie" is able to recreate a profile of the user, information valuable to advertising firms for research and targeting purposes. Supercookies were discovered to be in use on several websites by researchers from University of California at Berkeley and Stanford University.
Although the cookies are legal, both Microsoft and Hulu have decided to take action against them. A company called Kissmetrics was found to be responsible for Hulu's cookies, and when contacted by WSJ stated that they were planning to stop using them. On the other hand, Microsoft claimed they were unaware of the practices employed, and proceeded to remove the offending code.
Supercookies have a number of ways of bypassing the "clear cookies" system. Using Flash or HTML5, the cookie can instead reside in a local content cache. To get rid of them, Windows users can try CCleaner, a new version of which was released less than a month ago. Similar cleaners also exist for the Mac and Linux platforms.