Echoes in Orbit

hackthebox

Task: implement a CCSDS space-packet + AD-type TC transfer frame client (client.py skeleton with two empty stubs) to talk to a stateful onboard service on SCID 12 / APID 83 / VC 4 and issue GETFLAG. Solution: build the 6-byte space-packet and 5-byte TC-frame primary headers plus a CRC-16/CCITT-FALSE trailer, synchronize three independent counters (VCFC, SP sequence count, and a literal-ASCII per-message application counter), send '0x00:BEGIN' then '0x02:GETFLAG'.