All Writeups

Comprehensive collection of CTF challenges, solutions, and insights.

2026-06-07 Pentest Hard

DarkNet Services Stage 3 Penetration Test

Six-machine multi-subnet compromise chaining SSRF, XML injection, ECDSA nonce reuse, LFI, TOCTOU race condition, MCP prompt injection, Docker container forensics, network pivoting, and a fresh kernel exploit to root every host and capture all five flags.

ssrf xml-injection cve-2026-48778 ecdsa

2026-05-10 Crypto Medium

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.

crypto aes-gcm nonce-reuse ECHELON

2026-03-01 Crypto Hard

DEADROP Crypto 4 - DSA Again?

Two DSA signatures from the same key share an identical r value, a dead giveaway of nonce reuse. Recover the private key, forge a signature over the target authorization message, and submit it to the server.

dsa nonce-reuse private-key-recovery signature-forgery