Clear it in 3 steps
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Start the environment
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Investigate the target
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Submit the flag
All challenges
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Decode Custom Protocol C&C Communication
Mission
Analyze the endpoint beacon record `beacon.log` and decode the covert channel hidden among decoy traffic. Base64-decode the target host's data in sequence order, undo the single-byte XOR, and reconstruct the flag.
Hints
Hint 1 Show
Group beacons in beacon.log by destination host; most decode to status=... messages
Hint 2 Show
Only one host returns meaningless bytes -- that is the covert channel
Hint 3 Show
Base64-decode those beacons in seq order and XOR each byte with a one-byte key (brute-forceable) to get the flag