All Writeups

Comprehensive collection of CTF challenges, solutions, and insights.


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Raptor Weekly 2 - ECHELON Crypto 2 - 3.2 ; FREQUENCY

Recognizing a GCM nonce reuse vulnerability across two calibration reports, cancelling the keystream by XORing the ciphertexts, and recovering the anomaly report plaintext using a legacy diagnostic endpoint left running after decommission.

Raptor Weekly 2 - ECHELON Crypto 3 - 5.1 ; ECHELON

Assembling three named artifacts recovered across five prior challenges, a signing key exfiltrated in four fragments, a C2 handshake key, and a certificate-derived access key. Then computing their HMAC-SHA256 combination to authenticate to the CODEWORD tier.

Raptor Weekly 2 - ECHELON Crypto 1 - 2.2 ; DEAD DROP

Extracting an RC4 key hidden in a request ID header from the Tier 2 network capture and using it to decrypt an intercepted message that reveals the second half of a JWT signing secret.