Replay - EX-0001
Definition
Replay is the re-transmission of previously captured traffic, over RF links, crosslinks, or internal buses, to elicit the same processing and effects a second time. Adversaries first observe and record authentic exchanges (telecommands, ranging/acquisition frames, housekeeping telemetry acknowledgments, bus messages), then resend them within acceptance conditions that the system recognizes, matching link geometry, timetags, counters, or mode states. The aim can be functional (re-triggering an action such as a mode change), observational (fingerprinting how the vehicle reacts at different states), or disruptive (saturating queues and bandwidth to crowd out legitimate traffic). Because replays preserve valid syntax and often valid context, they can blend with normal operations, especially during periods with reduced monitoring or when counters and windows reset (e.g., handovers, safing entries). On encrypted links, metadata replays (acquisition beacons, schedule requests) may still yield informative responses.
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