posmv_input_plugin unauth UDP GPS spoofing into navigation.position (SOLAS-relevant)

Summary

Default ip='0.0.0.0' on UDP/5602 with no source allow-list, no HMAC, no replay protection. Forged Applanix POS-MV $GRP GID=1 frames write attacker coordinates to navigation.position/attitude/courseOverGroundTrue/rateOfTurn/speedOverGround. POS-MV is the authoritative position source on commercial vessels; ECDIS/autopilot/AIS-out all act on the forgery.

Impact

see PoC plus finding

Evidence — code citations

• research/audits/signalk/exploits/0428-...

Proof of concept