rules:
  - id: auth.py.crypto.ecb-mode
    languages:
      - python
    severity: WARNING
    message: |
      A symmetric cipher is configured in ECB mode. ECB encrypts each block
      independently, so identical plaintext blocks yield identical ciphertext,
      leaking structure and enabling block-shuffling attacks (CWE-327). This
      matters for anything auth-related: encrypted tokens, cookies, credentials.

      Use an authenticated mode: AES-GCM (`AESGCM` / `modes.GCM`) or, failing
      that, CBC with a random IV plus a separate MAC.
    pattern-either:
      - pattern: AES.new($K, AES.MODE_ECB, ...)
      - pattern: AES.new($K, $LIB.MODE_ECB, ...)
      - pattern: Cipher($ALG, modes.ECB(), ...)
      - pattern: Cipher($ALG, $M.modes.ECB(), ...)
      - pattern: modes.ECB()
    paths:
      exclude:
        - "**/test/**"
        - "**/test_*.py"
        - "**/*_test.py"
        - "**/conftest.py"
    metadata:
      oauthlint-rule-id: AUTH-PY-CRYPTO-002
      oauthlint-doc-url: https://oauthlint.dev/rules/py-crypto-ecb-mode
      category: security
      cwe: CWE-327
      owasp: A02:2021
      llm-prevalence: MEDIUM
      technology:
        - pycryptodome
        - cryptography
      references:
        - https://cwe.mitre.org/data/definitions/327.html