DEF CON 32 - GPS spoofing it's about time, not just position - Ken Munro

Talking to pilots and operators, an important aspect of GPS spoofing and jamming is being missed from the narrative in the media. We know about position spoofing, that's a given. What doesn't appear to be getting much attention is the effect of time spoofing. The most significant of these is an incident where time was spoofed a significant period into the future. This caused all digital certificates on board an aircraft to become invalid and caused all electronic communications to fail. As GPS clocks have protection against time being rolled backwards, but not forward, the aircraft was grounded for several weeks for systems to be reflashed and the clocks to be reset, Coarse time spoofing could therefore ground entire fleets. We'll discuss this and potential mitigations. If time allows, we could touch on conventional RF navaids and their exposure to similar attacks.