Timing side channels for traffic analysis
Xun Gong, Negar Kiyavash · 2013
Traffic analysis often requires direct observations of network connections at local vantage points. In this work, we show that traffic analysis can be performed remotely by taking advantage of a timing side channel. The timing side channel results from a shared resource, namely, the scheduler between two users. Utilizing Shannon equivocation as a privacy metric, we prove that one user can learn the complete traffic pattern of the other user if the scheduler employs a first come first serve (FCFS) policy. Moreover, we show the feasibility of a real system attack exploiting the timing side channel inside a home digital subscriber line (DSL) router. This demonstrates the magnitude of the threat timing side channels pose for traffic analysis.