We demonstrate the presence of a novel scheduler side-channel in preemptive,
fixed-priority real-time systems (RTS); examples of such systems can be found
in automotive systems, avionic systems, power plants and industrial control
systems among others. This side-channel can leak important timing information
such as the future arrival times of real-time tasks.This information can then
be used to launch devastating attacks, two of which are demonstrated here (on
real hardware platforms). Note that it is not easy to capture this timing
information due to runtime variations in the schedules, the presence of
multiple other tasks in the system and the typical constraints (e.g.,
deadlines) in the design of RTS. Our ScheduLeak algorithms demonstrate how to
effectively exploit this side-channel. A complete implementation is presented
on real operating systems (in Real-time Linux and FreeRTOS). Timing information
leaked by ScheduLeak can significantly aid other, more advanced, attacks in
better accomplishing their goals