SpyShield: Preserving privacy from spy add-ons

Spyware infections are becoming extremely pervasive, posing a grave threat to Internet users' privacy. Control of such an epidemic is increasingly difficult for the existing defense mechanisms, which in many cases rely on detection alone. In this paper, we propose SpyShield, a new containment technique, to add another layer of defense against spyware. Our technique can automatically block the visions of untrusted programs in the presence of sensitive information, which preserves users' privacy even after spyware has managed to evade detection. It also enables users to avoid the risks of using free software which could be bundled with surveillance code. As a first step, our design of SpyShield offers general protection against spy add-ons, an important type of spyware. This is achieved through enforcing a set of security policies to the channels an add-on can use to monitor its host application, such as COM interfaces and shared memory, so as to block unauthorized leakage of sensitive information. We prototyped SpyShield under Windows XP to protect Internet Explorer and also evaluated it using real plug-ins. Our experimental study shows that the technique can effectively disrupt spyware surveillance in accordance with security policies and introduce only a small overhead.