Chapter 15: Ubuntu Hardening and Patch Operations

Word target: 3,400
Primary deliverable: Practical Ubuntu hardening profile
Key diagrams: Layered defense model

Learning Goals

  • Apply host-level hardening suited to homelab operations.
  • Build predictable patch windows and emergency patch policy.
  • Measure and reduce exposed attack surface.

MVP Lab Worksheet

  • Objective: Implement baseline hardening controls.
  • Starting state: Ubuntu baseline active.
  • Steps:
    1. Configure firewall and service exposure.
    2. Enforce update policy and package hygiene.
    3. Validate hardening with checklist.
  • Evidence: Hardening checklist with pass/fail results.
  • Exit criteria: Critical controls enabled and verified.
  • Rollback: Restore previous firewall/service policy snapshot.

Advanced Lab Worksheet

  • Objective: Continuous security remediation loop.
  • Starting state: Baseline hardened.
  • Steps:
    1. Run periodic vulnerability scans.
    2. Prioritize findings by risk and exploitability.
    3. Remediate and retest.
  • Evidence: Scan diff report and closure log.
  • Exit criteria: High-risk findings closed within policy window.
  • Rollback: Revert risky remediations with change control record.
Portability Placeholder

Keep distro-specific hardening commands in sidebars, not core narrative.