---
id: hypnguyen1209/offensive-claude/crypto-analysis
version: "8e73c35f"
license: MIT
install: manual
updated: 2026-07-03
---

# crypto-analysis — Crypto-analysis evaluates cryptographic posture across TLS/SSL/SSH configurations, public-key implementations, and token schemes. It detects cipher downgrades, weak key generation, nonce reuse, AEAD misuse, and JWT algorithm confusion using integrated tools like testssl.sh, openssl, and hashcat. Use it to identify cryptographic flaws before attackers do.

Publisher: hypnguyen1209 · Stars: 326 · Updated: 2026-07-03

Install (manual): `git clone https://github.com/hypnguyen1209/offensive-claude`

## SKILL.md

# Cryptographic Analysis

## When to Activate

- Auditing TLS/SSL/SSH configurations and X.509 PKI (cipher suites, downgrade, protocol flaws)
- Reviewing crypto implementations in source code or captured traffic
- Attacking weak RSA/ECC keys (CTF and real-world weak-key hygiene)
- Recovering ECDSA/DSA private keys from reused or biased nonces (lattice/HNP)
- Exploiting symmetric/AEAD misuse: padding oracles, GCM nonce reuse, key-commitment
- Forging JWT/JOSE tokens (algorithm confusion, none, jwk/jku/kid injection)
- Cracking password hashes and grading KDF strength
- Assessing post-quantum readiness ("harvest now, decrypt later" exposure)

## Technique Map

| Technique | ATT&CK | CWE | Reference | Script |
|-----------|--------|-----|-----------|--------|
| TLS cipher/protocol downgrade audit | T1600.001 | CWE-326 | references/tls-pki-audit.md | scripts/tls_audit.py |
| Terrapin SSH prefix truncation (CVE-2023-48795) | T1557 | CWE-222 | references/tls-pki-audit.md | scripts/tls_audit.py |
| Marvin/Bleichenbacher RSA timing oracle | T1600 | CWE-208 | references/tls-pki-audit.md | scripts/tls_audit.py |
| X.509 / CT-log shadow-asset discovery | T1589 | CWE-295 | references/tls-pki-audit.md | scripts/tls_audit.py |
| RSA weak-key factoring (Fermat/Wiener/common-modulus) | T1600 | CWE-326 | references/rsa-attacks.md | scripts/rsa_attack.py |
| Coppersmith partial-key & ROCA (CVE-2017-15361) | T1600 | CWE-310 | references/rsa-attacks.md | scripts/rsa_attack.py |
| Hastad broadcast / batch-GCD | T1600 | CWE-326 | references/rsa-attacks.md | scripts/rsa_attack.py |
| ECDSA nonce reuse key recovery | T1552.004 | CWE-323 | references/ecc-nonce-attacks.md | scripts/ecdsa_lattice.py |
| Biased-nonce lattice/HNP (Minerva, PuTTY CVE-2024-31497) | T1552.004 | CWE-1241 | references/ecc-nonce-attacks.md | scripts/ecdsa_lattice.py |
| Psychic signature (0,0) (CVE-2022-21449) | T1606.001 | CWE-347 | references/ecc-nonce-attacks.md | scripts/ecdsa_lattice.py |
| CBC padding oracle (byte-by-byte decrypt) | T1040 | CWE-209 | references/symmetric-aead.md | scripts/padding_oracle.py |
| AES-GCM nonce reuse "forbidden attack" | T1040 | CWE-323 | references/symmetric-aead.md | scripts/gcm_nonce_reuse.py |
| AEAD key-commitment / invisible salamanders / partitioning oracle | T1606 | CWE-347 | references/symmetric-aead.md | scripts/gcm_nonce_reuse.py |
| JWT algorithm confusion RS256→HS256 (CVE-2024-54150) | T1606.001 | CWE-347 | references/jwt-jose.md | scripts/jwt_forge.py |
| JWT alg=none / jwk / jku / kid injection | T1606.001 | CWE-347 | references/jwt-jose.md | scripts/jwt_forge.py |
| Hash identification & GPU cracking | T1110.002 | CWE-916 | references/hash-pq.md | scripts/hash_triage.py |
| Weak KDF / fast-hash password storage | T1110.002 | CWE-916 | references/hash-pq.md | scripts/hash_triage.py |
| Post-quantum / HNDL exposure review | T1600 | CWE-327 | references/hash-pq.md | scripts/tls_audit.py |

## Quick Start

```bash
# 0. TLS/PKI posture in one shot (downgrade, ROBOT, SWEET32, Terrapin, cert/CT)
python3 scripts/tls_audit.py target.com:443 --ssh target.com:22 --ct --json out.json
testssl.sh --full --robot --sweet32 https://target.com   # cross-check with the canonical tool

# 1. RSA weak-key triage on a captured public key
python3 scripts/rsa_attack.py --pubkey server.pem --ct ciphertext.b64 --auto
#   tries Fermat (p~=q), Wiener (small d), batch-GCD/common-modulus, ROCA fingerprint

# 2. ECDSA key recovery from a signature corpus (reuse or bias)
python3 scripts/ecdsa_lattice.py recover sigs.json --curve secp256r1 --known-msb 4
#   reuse: needs 2 sigs w/ same r; bias: ~256-1200 sigs depending on leak

# 3. Symmetric/AEAD misuse
python3 scripts/padding_oracle.py --url https://t/dec --ct $CT --block 16   # CBC oracle
python3 scripts/gcm_nonce_reuse.py forbidden ct1.bin ct2.bin --nonce $N     # recover H + forge

# 4. JWT forgery chain
python3 scripts/jwt_forge.py confusion --pubkey jwt_pub.pem --claims '{"role":"admin"}'
python3 scripts/jwt_forge.py none      --claims '{"sub":"admin"}'

# 5. Hash triage + crack plan
python3 scripts/hash_triage.py hashes.txt            # identify + emit hashcat -m / john format
hashcat -m 22000 capture.hc22000 wl.txt -r rules/best64.rule
```

## OPSEC & Detection (summary)

| Technique | Telemetry / IOC | Detection (Sigma/EDR) | OPSEC note |
|-----------|-----------------|-----------------------|------------|
| TLS scanning / testssl | Burst of handshakes, many cipher renegotiations, malformed ClientHellos | NIDS: high TLS alert rate from one src; Zeek `ssl.log` anomalous cipher offers | Rate-limit, spread across source IPs; passive cert/CT recon leaves no target-side trace |
| Marvin/ROBOT oracle probing | ~10^4–10^6 RSA decrypts, repeated malformed pre-master/CMS | WAF/IDS: spike of TLS decrypt errors, identical-size payloads | Extremely loud; only against authorized hosts; use minimal query budgets |
| Terrapin MitM | Injected SSH_MSG_IGNORE, sequence-number gap at NEWKEYS | SSH server logs `kex` mismatch; netflow showing on-path device | Requires active MitM; detectable by strict-kex peers; abort if `kex-strict` present |
| ECDSA nonce harvesting | Bulk signature collection (Git, TLS, SSH, blockchain) | Mostly offline — no target telemetry once sigs captured | Collection is passive; recovery is offline; rotate-key advice in report |
| CBC padding oracle | Thousands of decrypt requests, alternating valid/invalid padding | Web logs: ~256×blocks requests to one endpoint; Sigma on 4xx burst | Very noisy (256×blocks×msgs); throttle, randomize timing |
| GCM nonce reuse / partitioning | Repeated (nonce,key) pairs; multi-key ciphertext blobs | App crypto audit; flag reused IVs in logs | Forbidden-attack math is offline once two ciphertexts captured |
| JWT forgery | Anomalous `alg`, external `jku`/`x5u` fetch, all-zero ES signature | Sigma: JWT with `alg:none`/HS after RS expected; egress to attacker JWKS URL | Each forged token is a single request; minimal noise |
| Hash cracking | None on target (offline) | N/A unless online spray (then T1110) | Offline; protect loot at rest; never spray live without scope |

## Deep Dives

- **references/tls-pki-audit.md** — TLS/SSL/SSH posture: cipher/protocol downgrade, Terrapin (CVE-2023-48795), Marvin/Bleichenbacher (CVE-2022-4304, CVE-2024-2236), SWEET32/DROWN/Logjam/POODLE, X.509 and Certificate-Transparency analysis.
- **references/rsa-attacks.md** — Weak-key factoring: Fermat, Wiener, common modulus, Hastad broadcast, Coppersmith partial-key, batch-GCD, ROCA (CVE-2017-15361); RsaCtfTool / cado-nfs / SageMath workflow.
- **references/ecc-nonce-attacks.md** — ECDSA/DSA nonce reuse, biased-nonce lattice/HNP recovery (Minerva, PuTTY CVE-2024-31497), invalid-curve attacks, psychic signatures (CVE-2022-21449).
- **references/symmetric-aead.md** — Block-cipher mode misuse: ECB detection, CBC padding oracle, CTR/GCM nonce reuse (forbidden attack), AEAD key-commitment / invisible salamanders / partitioning oracles.
- **references/jwt-jose.md** — JWT/JOSE token forgery: algorithm confusion (CVE-2024-54150), alg=none, jwk/jku/x5u/kid injection, weak-secret cracking, library-level CVE landscape.
- **references/hash-pq.md** — Hash identification, modern GPU cracking economics (RTX 40/50-series), KDF strength grading, and post-quantum migration / "harvest now, decrypt later" assessment (ML-KEM/ML-DSA, hybrid TLS, crypto-agility).


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