Cross-layer attack on anonymizing networks

Network layer anonymization protects only some of the userpsilas personal identification information, namely network addresses of the communicating parties. However, even if the lower layers of communication provide perfect protection for the userpsilas profile, information leakage on the application layer destroys the whole effort. Currently, all widespread implementations of anonymizing networks do not use a holistic approach and therefore, neither filter nor actively warn users about information leakage from the upper layers, which may look innocent to the end user. We extend existing work on security of anonymizing networks to take into account additional information leakage from the application layer. Further we show, under which conditions and how this kind of information can be used not only to build an extensive user profile at ldquolow costsrdquo, but also to speed up traditional attacks that are targeted at the network layer identification of userspsila peer partners.