Google was caught last week bypassing default privacy settings in the Safari browser in order to serve up tracking cookies. The company claimed the situation was an accident and limited only to the Safari Web browser, but today Microsoft claimed Google is doing much the same thing with Internet Explorer.
In a blog post titled "Google bypassing user privacy settings" Microsoft's IE Corporate Vice President Dean Hachamovitch states that "When the IE team heard that Google had bypassed user privacy settings on Safari, we asked ourselves a simple question: is Google circumventing the privacy preferences of Internet Explorer users too? We’ve discovered the answer is yes: Google is employing similar methods to get around the default privacy protections in IE and track IE users with cookies."
Hachamovitch explains that IE's default configuration blocks third-party cookies unless presented with a "P3P (Platform for Privacy Preferences Project) Compact Policy Statement" indicating that the site will not use the cookie to track the user. Microsoft accuses Google of sending a string of text that tricks the browser into thinking the cookie won't be used for tracking. "By sending this text, Google bypasses the cookie protection and enables its third-party cookies to be allowed rather than blocked," Microsoft said.
The text allegedly sent by Google actually reads "This is not a P3P policy" and includes a link to a Google page which says cookies used to secure and authenticate Google users are needed to store user preferences, and that the P3P protocol "was not designed with situations like these in mind."
Microsoft said it has contacted Google to ask the company to "commit to honoring P3P privacy settings for users of all browsers." Microsoft also updated the Tracking Protection Lists in IE9 to prevent the tracking described by Hachamovitch in the blog post. Ars has contacted Google to see if the company has any response to the Microsoft allegations, and we'll update this post if we hear back.
UPDATE: It turns out Facebook and many other sites are using an almost identical scheme to override Internet Explorer's privacy setting, according to a privacy researcher at Carnegie Mellon University. "Companies have discovered that they can lie in their [P3P policies] and nobody bothers to do anything about it," the researcher writes.