System & Network Hardening Checklist
An executable hardening checklist across the Prevent / Harden / Verify domains: configuration, patching, access and verification actions.
Quick Answer
Harden systems by removing default/over-broad access, enforcing strong authentication and patching, restricting unnecessary services, validating security headers/DNS/email controls, and re-verifying configurations on a schedule.
Definition
A directly executable hardening checklist that turns prevention and verification into discrete configuration, patching and access-control actions.
Before (baseline)
- Inventory assets, versions and exposed services; map their business criticality.
- Establish a configuration baseline (CIS benchmarks) and a patch lifecycle (
security:patch-management).
During (harden)
- Disable or remove default accounts, unmanaged admin shells and unnecessary services (reduce attack surface).
- Enforce MFA on privileged and remote access (
security:identity-mfa). - Apply least-privilege authorization; review over-broad permissions (
security:authentication-authorization). - Apply the latest critical patches; close the most-exposed/KEV CVEs first (
guides:tool-cve-guide). - Correct known misconfigurations (exposed dashboards, open ports, world-readable secrets) per
security:misconfiguration. - Verify external endpoints: security headers (
guides:tool-headers-guide), email/DMARC posture (security:email-security), DNS/record hygiene (guides:tool-dns-guide).
After (verify)
- Re-run endpoint checks to confirm headers/records are fixed.
- Confirm no backdoor accounts or unexpected scheduled tasks/persistence.
- Re-baseline and store a verified configuration snapshot.
Verification & escalation
- Remediation verified by re-scan, not by intent.
- Escalate any discovered P0 gap (already-exploited KEV vulnerability or exposed credentials) to the response team.
Pair with guides:threat-detection-response-checklist and guides:incident-response-playbook.
References
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