A top security researcher has called for Microsoft to rethink aspects of its Suggested Sites feature in IE8. The optional feature in the next version of Microsoft's browser allows users to "discover websites you might like based on sites you've visited", as Microsoft explains it.
Microsoft was able to allay concerns that data from secure sites might be sampled or that the feature might be used to serve up targeted advertising in response to our earlier queries on the technology, prompted in response to posts by privacy activists on the No Deep Packet Inspection campaign website. However, concerns about the privacy implications of the technology remain.
Cambridge University security researcher Richard Clayton, who carried out an analysis of Phorm for the Foundation for Information Policy Research (FIPR), said full URL sharing via Suggested Sites poses a privacy and security risk. In particular he warns Microsoft should avoid sharing data submitted by surfers with other users of the service.
Microsoft should be clearer about explaining the risks as well as the benefits of the service, he adds.
In order for Microsoft to suggest other websites that you might like to look at, they need to know where you've been visiting lately. If you're embarrassed about saying where that is, then you leave the new feature turned off and no harm is done.
However, if you turn it on, then it appears that you hand over the entire URL of where you've visited. On some sites that's essential: if you've been on blogger.com, then knowing which of the eight million blogs you visited will matter. However, on other sites, that full URL may hold clues to your identity, give permissions to others to access the site, or compromise your privacy or security in some other manner.
The risk that someone at Microsoft decides to use that URL for wickedness are rather small - but what if they hand off the URL to someone else with similar tastes, for them to try visiting the places that you go to. Suddenly all that "security through obscurity", the pious hope that no one could possibly guess that URL, goes up in smoke.
Microsoft could do better, by minimising the data transfer, and only obtaining longer URLs for the sites, like blogger.com, where it actually matters. In the meantime, they should spell out the risks up front, along with the benefits... or did they genuinely think that there weren't any risks?
Clayton's response, which came in response to a request by El Reg for his opinion on the privacy implications of the technology, moves on the debate about whether Suggested Sites allows users a richer surfing experience or creates more problems than it solves.
Microsoft told us that when InPrivate (aka pron surfing) mode is applied within IE8, then Suggested Sites is temporarily turned off. "Data about secure HTTPS sites visited, intranet sites or local files on the PC" is excluded at all times, it added.