https://th3b0ywh0l1v3d.github.io/tags/xor/ Recent content in XOR on Th3B0yWh0L1v3d — Security Writeups Hugo en-us Tue, 16 Jun 2026 00:00:00 +0000 https://th3b0ywh0l1v3d.github.io/ctf/boroctf-2026/reversing/cat/ Tue, 16 Jun 2026 00:00:00 +0000 https://th3b0ywh0l1v3d.github.io/ctf/boroctf-2026/reversing/cat/ Reversing a repeating-key XOR crackme that downloads the flag from catbox.moe. https://th3b0ywh0l1v3d.github.io/ctf/boroctf-2026/reversing/hidden-but-definitely-not/ Tue, 16 Jun 2026 00:00:00 +0000 https://th3b0ywh0l1v3d.github.io/ctf/boroctf-2026/reversing/hidden-but-definitely-not/ Recovering a flag hidden via stack-string construction and XOR obfuscation. https://th3b0ywh0l1v3d.github.io/ctf/dalctf-2026/pwning/bandaids-help-me-heal/ Sun, 07 Jun 2026 00:00:00 +0000 https://th3b0ywh0l1v3d.github.io/ctf/dalctf-2026/pwning/bandaids-help-me-heal/ A ‘pwn’ binary with no input is really a static-reversing puzzle: a fake usleep loop would take days and a fake integrity check always passes, so reading the constants and undoing a single-byte XOR yields the flag without ever waiting. https://th3b0ywh0l1v3d.github.io/ctf/dalctf-2026/crypto/fun-with-rsa/ Sun, 07 Jun 2026 00:00:00 +0000 https://th3b0ywh0l1v3d.github.io/ctf/dalctf-2026/crypto/fun-with-rsa/ A homemade RSA-CRT signer leaks a correct and a faulted signature of the same message; gcd(s − spz, n) factors n (the Bellcore attack), while the trivial shortcut just recovers the message via s^e mod n — and the XOR ‘protection’ undoes itself. https://th3b0ywh0l1v3d.github.io/ctf/gpn-ctf-2026/web/secretpickle/ Sat, 06 Jun 2026 00:00:00 +0000 https://th3b0ywh0l1v3d.github.io/ctf/gpn-ctf-2026/web/secretpickle/ A Pyodide client serializes requests with pickle obfuscated by a hardcoded XOR key, letting the server pickle.loads attacker data for unauthenticated root RCE, then hooking the live handler to capture the adminbot’s plaintext login password.