Tutorial 25 — Security Hardening

A practical guide to hardening agent deployments using the Agent Governance Toolkit's built-in security tooling. This tutorial covers secret scanning, dependency review, static analysis, fuzz testing, supply chain security, and branch protection — everything you need to secure a production agent system.

Scope: CI/CD security, dependency management, code analysis, fuzzing Frameworks: Gitleaks, Dependabot, CodeQL, ClusterFuzzLite, OpenSSF Scorecard Audience: Platform engineers and security teams deploying governed agents

What you'll learn

Section	Topic
Security Overview	Defence-in-depth for agent systems
Secret Scanning	Prevent secrets from entering the repository
Dependency Review	Automated CVE scanning across 13 ecosystems
CodeQL Analysis	Static analysis for Python and TypeScript
Fuzz Testing	7 fuzz targets for parser and policy code
OpenSSF Scorecard	Automated security scoring
SBOM Generation	SPDX and CycloneDX software bills of materials
Branch Protection	Enforcing CI gates
Recommendations	Production deployment checklist

Prerequisites

A GitHub repository with GitHub Actions enabled
Familiarity with CI/CD workflows
Recommended: read Tutorial 04 — Audit & Compliance

Security Overview

The Agent Governance Toolkit uses a defence-in-depth approach with multiple overlapping security layers:

  ┌─────────────────────────────────────────────────────┐
  │                   Branch Protection                 │
  │  ┌───────────────────────────────────────────────┐  │
  │  │              CI Security Gates                │  │
  │  │  ┌─────────────────────────────────────────┐  │  │
  │  │  │         Static Analysis (CodeQL)        │  │  │
  │  │  │  ┌───────────────────────────────────┐  │  │  │
  │  │  │  │     Dependency Review (Dependabot) │  │  │  │
  │  │  │  │  ┌─────────────────────────────┐  │  │  │  │
  │  │  │  │  │  Secret Scanning (Gitleaks) │  │  │  │  │
  │  │  │  │  │  ┌───────────────────────┐  │  │  │  │  │
  │  │  │  │  │  │   Fuzz Testing        │  │  │  │  │  │
  │  │  │  │  │  └───────────────────────┘  │  │  │  │  │
  │  │  │  │  └─────────────────────────────┘  │  │  │  │
  │  │  │  └───────────────────────────────────┘  │  │  │
  │  │  └─────────────────────────────────────────┘  │  │
  │  └───────────────────────────────────────────────┘  │
  └─────────────────────────────────────────────────────┘

Secret Scanning with Gitleaks

Gitleaks detects hardcoded secrets (API keys, tokens, passwords) before they reach the repository.

How It Works

The toolkit includes a Gitleaks configuration that scans every commit for:

API keys and tokens
Connection strings
Private keys
Cloud credentials (AWS, Azure, GCP)

CI Integration

# .github/workflows/gitleaks.yml
name: Gitleaks Secret Scan
on: [push, pull_request]

jobs:
  gitleaks:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0
      - uses: gitleaks/gitleaks-action@v2
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

Local Pre-Commit Hook

Run Gitleaks locally before pushing:

# Install Gitleaks
brew install gitleaks  # macOS
# or download from https://github.com/gitleaks/gitleaks/releases

# Scan the repo
gitleaks detect --source . --verbose

# Scan only staged changes (pre-commit)
gitleaks protect --staged --verbose

Allowlisting False Positives

Use the .gitleaksignore file for known false positives:

# .gitleaksignore
# Test fixtures with fake credentials
tests/fixtures/mock-credentials.json

Best practice: Never add real secrets to the allowlist. Use environment variables or a secret manager instead.

Dependency Review and Dependabot

The toolkit uses Dependabot to monitor dependencies across 13 ecosystems:

Ecosystem	Config File	Scope
Python (pip)	`requirements/*.txt`	Core packages
Python (pip)	`packages/*/requirements.txt`	Per-package
Node.js (npm)	`packages/*/package.json`	TypeScript SDK
.NET (NuGet)	`*.csproj`	.NET SDK
Rust (Cargo)	`Cargo.toml`	Rust SDK
Go (modules)	`go.mod`	Go SDK
GitHub Actions	`.github/workflows/*.yml`	CI/CD
Docker	`Dockerfile`	Container images

Dependabot Configuration

# .github/dependabot.yml
version: 2
updates:
  - package-ecosystem: pip
    directory: "/"
    schedule:
      interval: weekly
    labels:
      - "dependencies"
      - "security"
    open-pull-requests-limit: 10

  - package-ecosystem: npm
    directory: "/packages/agent-mesh/sdks/typescript"
    schedule:
      interval: weekly

  - package-ecosystem: github-actions
    directory: "/"
    schedule:
      interval: weekly

Dependency Confusion Prevention

The toolkit includes a script that checks for dependency confusion attacks:

python scripts/check_dependency_confusion.py

This verifies that internal package names don't conflict with public registries.

Weekly Security Audit

A weekly workflow runs comprehensive dependency checks:

# Runs every Monday at 08:00 UTC
on:
  schedule:
    - cron: '0 8 * * 1'

It checks for:

Known CVEs in dependencies (via safety and pip-audit)
Dependency confusion risks
Weak cryptography usage (hashlib.md5, hashlib.sha1)
Unsafe pickle usage in non-test code

CodeQL Analysis

CodeQL performs deep static analysis to find security vulnerabilities in Python and TypeScript code.

Detected Vulnerability Classes

Language	Vulnerabilities
Python	SQL injection, command injection, path traversal, SSRF, XSS, unsafe deserialization
TypeScript	Prototype pollution, ReDoS, XSS, injection, insecure randomness

CI Integration

# .github/workflows/codeql.yml
name: CodeQL Analysis
on:
  push:
    branches: [main]
  pull_request:
    branches: [main]
  schedule:
    - cron: '0 6 * * 1'  # weekly

jobs:
  analyze:
    runs-on: ubuntu-latest
    permissions:
      security-events: write
    strategy:
      matrix:
        language: [python, javascript]
    steps:
      - uses: actions/checkout@v4
      - uses: github/codeql-action/init@v3
        with:
          languages: ${{ matrix.language }}
      - uses: github/codeql-action/analyze@v3

Custom Queries

For agent-specific vulnerabilities, add custom CodeQL queries:

// queries/unsafe-tool-call.ql
import python

from Call call, Attribute attr
where
  attr = call.getFunc().(Attribute) and
  attr.getName() = "execute" and
  not exists(call.getArg(0).(StringLiteral))
select call, "Dynamic tool execution without static action name"

Fuzz Testing with ClusterFuzzLite

The toolkit includes 7 fuzz targets that test parser and policy code with randomised inputs.

Fuzz Targets

Target	Component	Purpose
`fuzz_policy_parser`	Policy engine	Malformed YAML policy files
`fuzz_mcp_scanner`	MCP security	Malicious tool descriptions
`fuzz_prompt_injection`	Prompt guard	Adversarial prompt inputs
`fuzz_trust_scoring`	Trust manager	Edge-case trust calculations
`fuzz_audit_chain`	Audit logger	Hash-chain integrity under stress
`fuzz_identity`	Agent identity	Malformed DID and key inputs
`fuzz_context_budget`	Budget scheduler	Extreme allocation patterns

Running Fuzz Tests Locally

# Install the fuzzer
pip install atheris  # Python fuzzer

# Run a specific target
python -m pytest tests/fuzz/test_fuzz_policy.py -x --timeout=60

CI Integration with ClusterFuzzLite

# .github/workflows/fuzz.yml
name: ClusterFuzzLite
on:
  pull_request:
    branches: [main]

jobs:
  fuzz:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: google/clusterfuzzlite/actions/build_fuzzers@v1
        with:
          language: python
      - uses: google/clusterfuzzlite/actions/run_fuzzers@v1
        with:
          fuzz-seconds: 300
          mode: code-change

OpenSSF Scorecard

The OpenSSF Scorecard automatically scores the repository's security posture across multiple dimensions.

Scorecard Checks

Check	What It Verifies
`Binary-Artifacts`	No checked-in binaries
`Branch-Protection`	Required reviews, status checks
`Code-Review`	All changes go through review
`Dangerous-Workflow`	No `pull_request_target` with secrets
`Dependency-Update-Tool`	Dependabot or Renovate configured
`Fuzzing`	Fuzz testing in CI
`License`	OSI-approved licence present
`Maintained`	Recent commits and issue responses
`Pinned-Dependencies`	Actions pinned to SHA
`SAST`	Static analysis (CodeQL) enabled
`Security-Policy`	SECURITY.md present
`Signed-Releases`	Release artifacts are signed
`Token-Permissions`	Minimal GitHub token permissions
`Vulnerabilities`	No known CVEs in dependencies

CI Integration

# .github/workflows/scorecard.yml
name: OpenSSF Scorecard
on:
  push:
    branches: [main]
  schedule:
    - cron: '0 6 * * 1'

jobs:
  scorecard:
    runs-on: ubuntu-latest
    permissions:
      security-events: write
      id-token: write
    steps:
      - uses: actions/checkout@v4
      - uses: ossf/scorecard-action@v2
        with:
          results_file: scorecard-results.sarif
          publish_results: true
      - uses: github/codeql-action/upload-sarif@v3
        with:
          sarif_file: scorecard-results.sarif

SBOM Generation

Software Bills of Materials (SBOMs) list every component in the software supply chain. The toolkit generates both SPDX and CycloneDX formats.

Automated SBOM Workflow

# .github/workflows/sbom.yml (simplified)
name: SBOM Generation
on:
  release:
    types: [published]

jobs:
  sbom:
    runs-on: ubuntu-latest
    permissions:
      contents: write
      id-token: write
      attestations: write
    steps:
      - uses: actions/checkout@v4

      # Generate SPDX SBOM
      - uses: anchore/sbom-action@v0
        with:
          output-file: sbom.spdx.json
          format: spdx-json

      # Generate CycloneDX SBOM
      - uses: anchore/sbom-action@v0
        with:
          output-file: sbom.cdx.json
          format: cyclonedx-json

      # Attest SBOM to the release
      - uses: actions/attest-sbom@v2
        with:
          subject-path: sbom.spdx.json

For more details on SBOM signing and verification, see Tutorial 26 — SBOM and Signing.

Branch Protection and Required Status Checks

Recommended Branch Protection Rules

Setting	Value	Reason
Require pull request reviews	1+ reviewers	Code review before merge
Dismiss stale reviews	Enabled	Re-review after changes
Require status checks	Enabled	CI must pass
Require branches up to date	Enabled	No stale merges
Require signed commits	Recommended	Commit integrity
Include administrators	Enabled	No bypass

Required Status Checks

Configure these as required status checks for pull requests:

✅ ci / lint
✅ ci / test-python
✅ ci / test-typescript
✅ ci / test-dotnet
✅ ci / security-scan
✅ gitleaks / scan
✅ codeql / analyze (python)
✅ codeql / analyze (javascript)

Setting Up via GitHub CLI

# Enable branch protection
gh api repos/{owner}/{repo}/branches/main/protection \
  --method PUT \
  --field required_pull_request_reviews='{"required_approving_review_count":1}' \
  --field required_status_checks='{"strict":true,"contexts":["ci / test-python","ci / security-scan"]}' \
  --field enforce_admins=true

Recommendations for Production

Deployment Checklist

Secrets: All secrets in a secret manager (Azure Key Vault, AWS Secrets Manager, HashiCorp Vault) — never in environment variables or config files
Gitleaks: Running on every push and pull request
Dependabot: Configured for all package ecosystems
CodeQL: Running on push to main and weekly schedule
Fuzz testing: Running on pull requests
SBOM: Generated on every release
Branch protection: Enabled with required reviews and status checks
Scorecard: Running weekly with results published

Security Scanning Script

The toolkit includes a built-in security scanner for plugin directories:

# Scan all packages with minimum severity of "high"
python scripts/security_scan.py packages/ \
  --exclude-tests \
  --min-severity high \
  --format text

The scanner checks for:

Secrets via detect-secrets
Python CVEs via pip-audit
Node vulnerabilities via npm audit
Dangerous code patterns via bandit
Risky code snippets in markdown skill files

Severity levels and blocking behaviour:

Severity	Action
`critical`	Blocks merge
`high`	Blocks merge
`medium`	Warning only
`low`	Informational

Security Exemptions

For known false positives, create a .security-exemptions.json:

{
  "version": "1.0",
  "exemptions": [
    {
      "tool": "detect-secrets",
      "category": "High Entropy String",
      "file": "tests/fixtures/mock-data.json",
      "reason": "Test fixture with fake data",
      "approved_by": "security-team",
      "ticket": "SEC-1234",
      "temporary": true,
      "expires": "2025-12-31"
    }
  ]
}

Cross-Reference

Concept	Tutorial
Audit trails	Tutorial 04 — Audit & Compliance
MCP security scanning	Tutorial 07 — MCP Security Gateway
Compliance verification	Tutorial 18 — Compliance Verification
SBOM and signing	Tutorial 26 — SBOM and Signing
MCP scan CLI	Tutorial 27 — MCP Scan CLI
Plugin marketplace security	Tutorial 10 — Plugin Marketplace

Next Steps

Run the Scorecard locally to see your current security posture:

scorecard --repo=github.com/your-org/your-repo

Enable Dependabot for all package ecosystems in your repository
Add fuzz targets for any custom parser or policy code
Configure branch protection with the recommended settings above
Read Tutorial 26 (SBOM and Signing) for supply chain security

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Tutorial 25 — Security Hardening

What you'll learn

Prerequisites

Security Overview

Secret Scanning with Gitleaks

How It Works

CI Integration

Local Pre-Commit Hook

Allowlisting False Positives

Dependency Review and Dependabot

Dependabot Configuration

Dependency Confusion Prevention

Weekly Security Audit

CodeQL Analysis

Detected Vulnerability Classes

CI Integration

Custom Queries

Fuzz Testing with ClusterFuzzLite

Fuzz Targets

Running Fuzz Tests Locally

CI Integration with ClusterFuzzLite

OpenSSF Scorecard

Scorecard Checks

CI Integration

SBOM Generation

Automated SBOM Workflow

Branch Protection and Required Status Checks

Recommended Branch Protection Rules

Required Status Checks

Setting Up via GitHub CLI

Recommendations for Production

Deployment Checklist

Security Scanning Script

Security Exemptions

Cross-Reference

Next Steps

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Tutorial 25 — Security Hardening

What you'll learn

Prerequisites

Security Overview

Secret Scanning with Gitleaks

How It Works

CI Integration

Local Pre-Commit Hook

Allowlisting False Positives

Dependency Review and Dependabot

Dependabot Configuration

Dependency Confusion Prevention

Weekly Security Audit

CodeQL Analysis

Detected Vulnerability Classes

CI Integration

Custom Queries

Fuzz Testing with ClusterFuzzLite

Fuzz Targets

Running Fuzz Tests Locally

CI Integration with ClusterFuzzLite

OpenSSF Scorecard

Scorecard Checks

CI Integration

SBOM Generation

Automated SBOM Workflow

Branch Protection and Required Status Checks

Recommended Branch Protection Rules

Required Status Checks

Setting Up via GitHub CLI

Recommendations for Production

Deployment Checklist

Security Scanning Script

Security Exemptions

Cross-Reference

Next Steps