Skill v1.0.3
currentAutomated scan100/1002 files
version: "1.0.3" name: auditing-python-security description: Audits Python libraries for security vulnerabilities using Bandit, pip-audit, Semgrep, and detect-secrets. Identifies SQL injection, command injection, hardcoded credentials, secrets exposed through tracebacks, weak cryptography, and insecure deserialization. Use when reviewing library security, setting up security scanning in CI, or implementing secure coding patterns.
Python Security Auditing
Quick Start
# Run all four scanners (gates CI): exit 1 on a blocking finding, exit 2 when a# requested scanner could not run, exit 0 only when every scanner ran clean:uv run python scripts/security_scan.py .# Tolerate scanners that are missing or hung (restores exit 0 in that case):uv run python scripts/security_scan.py . --allow-scanner-failure# Or individually:uvx bandit -r src/ -ll # High-severity static analysisuvx pip-audit . # This project's dependenciesuvx semgrep --config auto src/ # Pattern-based SASTuvx detect-secrets scan > .secrets.baseline # Secrets detection
Tool Configuration
Bandit (.bandit):
exclude_dirs: [tests/, docs/, .venv/]skips: [B101] # assert_used - OK in tests
pip-audit:
uvx pip-audit -r requirements.txt # Scan requirementsuvx pip-audit --fix # Auto-fix vulnerabilities
Common Vulnerabilities
| Issue | Bandit ID | Fix | |
|---|---|---|---|
| SQL injection | B608 | Use parameterized queries | |
| Command injection | B602 | subprocess without shell=True | |
| Hardcoded secrets | B105, B106 | Environment variables | |
| Weak crypto | B303 | Use SHA-256+, bcrypt for passwords | |
| Pickle untrusted data | B301 | Use JSON instead | |
| Path traversal | B108 | Validate with Path.resolve() |
Secure Patterns
# SQL - Parameterized queryconn.execute("SELECT * FROM users WHERE id = ?", (user_id,))# Commands - No shellsubprocess.run(["cat", filename], check=True)# Secrets - EnvironmentAPI_KEY = os.environ.get("API_KEY")# Paths - Validatebase = Path("/data").resolve()file_path = (base / filename).resolve()if not file_path.is_relative_to(base):raise ValueError("Invalid path")
Tracebacks Must Not Dump Frame Locals
Rich exception renderers can print every local variable in every stack frame. That turns an ordinary unhandled exception into a credential leak: API tokens, authorization headers, request bodies, and decrypted configuration commonly live in locals when the traceback is rendered to a terminal or CI log.
Keep local-variable rendering disabled anywhere logs can leave the developer's machine:
from rich.traceback import installinstall(show_locals=False)
Do not stop at asserting the configuration call. Exercise the installed exception hook with a sentinel secret and inspect the rendered output. This catches a later refactor that replaces the hook or re-enables locals elsewhere:
import sysdef test_unhandled_traceback_does_not_expose_locals(capsys):sentinel = "sentinel-secret-that-must-not-appear"try:raise RuntimeError("boom")except RuntimeError:exc_type, exc, traceback = sys.exc_info()sys.excepthook(exc_type, exc, traceback)output = capsys.readouterr()rendered = output.out + output.errassert "RuntimeError: boom" in rendered # proves the hook renderedassert sentinel not in rendered
Use a unique sentinel, never a real credential. Assert both that the exception was rendered and that the sentinel was absent; an empty or bypassed output path must not make the security test pass vacuously.
CI Integration
# .github/workflows/security.yml — full workflow in CI_SECURITY.md- uses: astral-sh/setup-uv@v5- run: uv run python scripts/security_scan.py . --output security-report.json
For detailed patterns, see:
- scripts/security_scan.py — runs all four scanners and exits non-zero on blocking findings (exit 1) or on a requested scanner that could not run (exit 2, opt out with
--allow-scanner-failure) (uv run python scripts/security_scan.py .) - [VULNERABILITIES.md](VULNERABILITIES.md) - Vulnerability classes with vulnerable→fixed pairs
- [CI_SECURITY.md](CI_SECURITY.md) - Complete CI workflow, pre-commit, Dependabot, triage
Audit Checklist
Code:- [ ] No SQL injection (parameterized queries)- [ ] No command injection (no shell=True)- [ ] No hardcoded secrets- [ ] Exception and logging configuration cannot render frame locals containing secrets- [ ] No weak crypto (MD5/SHA1)- [ ] Input validation on external data- [ ] Path traversal prevention- [ ] SSRF fetches connect to the validated IP on every redirect hop (DNS rebinding safe)- [ ] SSRF deny policy covers IPv4/IPv6 and CGNAT (`100.64.0.0/10`)Dependencies:- [ ] pip-audit clean- [ ] Minimal dependencies- [ ] From trusted sourcesCI:- [ ] Security scan on every PR- [ ] Weekly dependency scan
Learn More
This skill is based on the Security section of the Guide to Developing High-Quality Python Libraries by Will McGinnis. See these posts for deeper coverage: