Menu

Individual skill

offensive-crypto-attacks

Systematic methodology for identifying and exploiting cryptographic implementation weaknesses in real-world applications. Covers padding oracle attacks against CBC-mode ciphers with PKCS7 padding (Vaudenay's original attack through modern padbuster automation), ECB mode exploitation including block cut-and-paste and byte-at-a-time decryption, hash length extension attacks against SHA1/SHA256/MD5-based MACs using HashPump, RSA vulnerabilities including small public exponent, common modulus, Bleichenbacher PKCS1v1.5 padding oracle, and Coppersmith's method for partial key recovery. Addresses weak PRNG exploitation targeting time-seeded generators and Mersenne Twister MT19937 state recovery from observed outputs, timing side-channel attacks against comparison operations, nonce reuse in AES-GCM leading to authentication key recovery, and key derivation weaknesses including insufficient iteration counts and missing salts. Primary tooling includes padbuster, RsaCtfTool, hashpump, and PyCryptodome for building custom exploit payloads. Maps to CWE-327 (Use of a Broken or Risky Cryptographic Algorithm), CWE-328 (Use of Weak Hash), and CWE-330 (Use of Insufficiently Random Values). Emphasizes black-box identification of vulnerable implementations before transitioning to targeted exploitation.

Skills/crypto/offensive-crypto-attacks/SKILL.md

Read pinned source

Source commit a8de813edc9f66f60d44cfe42d47750e89d9930b

What was checked

Matches the observed repository HEAD
Yes
Scanner rules are current
Yes
Repository scan complete
No
Skill scan complete
No
Observed behavior
Network or broad shell
Last checked
Nov 2, 2026

These are observations at the recorded commit, not a guarantee of safety. Review the source before running it.

Install this skill

Choose an agent in your Stack or copy a command below. Commands fetch the pinned commit and copy only this skill directory. Existing destinations are refused. Copying a command does not install anything.

An install command is unavailable: current rules, complete repository and skill scans, an eligible behavior level and a permitted license are required.

Repository context

Repository stars (not skill ratings)
10,460
Repository last updated
Oct 12, 2026
License
MIT

Observed agent integration: No specific integration evidence. Standard SKILL.md installation does not imply verified compatibility.

Files and excerpt

File metadata and permitted, redacted excerpts come from the recorded scan. Source links are pinned to that commit.

Browse files
Read excerpt

# Cryptographic Implementation Attacks

You are performing offensive cryptographic analysis against target applications. This skill covers the identification and exploitation of flawed cryptographic implementations -- not breaks against the underlying mathematical primitives, but against the ways developers misuse them. You treat every encrypted blob, signed token, and hashed value as a potential attack surface.

## Quick Workflow

1. Identify cryptographic touchpoints -- cookies, tokens, API parameters, stored credentials, signed URLs.
2. Fingerprint the algorithm and mode -- measure ciphertext length behavior, detect block alignment, check for Base64/hex encoding layers.
3. Classify the vulnerability class -- padding oracle, ECB determinism, weak MAC construction, RSA parameter weakness, PRNG predictability.
4. Select and configure the appropriate tool or custom script.
5. Execute the attack, decrypt or forge the target value.
6. Document the cryptographic weakness, its root cause, and the remediation path.

---