Security Monitoring Guide for Continuous Protection

Small issues become incidents when they go unnoticed. An expired certificate, a missing header, a debug page left open. Good security monitoring catches drift early so fixes are fast and outages are avoided.

What website security monitoring covers

Inventory your surface: domains, subdomains, key routes, public APIs
Transport health: HTTPS on every route, single hop HTTP to HTTPS redirects, HSTS present
TLS posture: modern protocols and ciphers, no legacy versions reintroduced
Browser defenses: CSP, Referrer-Policy, X-Content-Type-Options, frame-ancestors
Content integrity: no mixed content, correct cache controls on sensitive pages
Exposure checks: open ports, test dashboards, unauthenticated admin paths
DNS and email: correct A/AAAA/CNAME, SPF and DMARC in place

Simple KPIs to track

HTTPS coverage: percent of routes serving HTTPS with a single hop redirect
Header coverage: percent of pages with baseline headers (HSTS, CSP mode, XCTO, Referrer-Policy)
TLS posture: oldest protocol seen in the last 7 days and target set
Time to detect: median time from drift to alert
Time to restore: median time from alert to baseline restored

A practical setup you can maintain

Build a small inventory of your most important pages and APIs (home, login, checkout, dashboard, public API routes)
Establish a baseline: what headers, TLS versions, redirects, and DNS look like when healthy
Schedule weekly checks and alerts for changes from that baseline
Add quick CI checks on critical routes so regressions are caught before release
Assign ownership and add short playbooks so fixes are repeatable

Baseline checklist you can copy

HTTPS on every route, HTTP to HTTPS is single hop
HSTS present with a sensible max-age and includeSubDomains when ready
CSP enabled, initially with Report-Only mode, then enforce when violations are near zero
Referrer-Policy set to a privacy conscious value (for example strict-origin-when-cross-origin)
X-Content-Type-Options set to nosniff
TLS 1.3 enabled, strong ciphers preferred, no legacy protocols in use
No mixed content errors on key pages
SPF and DMARC records present and valid

Quick CI checks (copy and paste)

Single hop redirect check

code=$(curl -s -o /dev/null -w "%{http_code}" http://example.com)
loc=$(curl -s -I http://example.com | awk -F': ' '/^Location:/{print $2}')
test "$code" = "301" && echo "$loc" | grep -q "https://example.com/" || { echo "Redirect not single hop to canonical HTTPS"; exit 1; }

Header presence check

curl -s -I https://example.com | grep -qi "strict-transport-security" || { echo "Missing HSTS"; exit 1; }
curl -s -I https://example.com | grep -qi "x-content-type-options: nosniff" || { echo "Missing XCTO"; exit 1; }

No mixed content on a page

Simple grep on HTML as a smoke test:

curl -s https://example.com | grep -q "http://" && { echo "Potential mixed content strings found"; exit 1; } || true

High‑value checks and processes

Certificate expiry

Alert at 30, 14, and 7 days
Auto renew via ACME where possible, then verify chain and HSTS after renewal

Header regression

Restore the baseline header set
Add a CI rule that fails if required headers are removed

Mixed content

Fix sources in templates, CSS, JS, and CMS content
Use upgrade-insecure-requests only as a bridge during cleanup

API drift

Enforce rate limits and authorization checks on sensitive routes
Alert on anomalies like spikes in 401 or 429

Weekly cadence that actually works

Monday: review changes and alerts from the past week, keep it to 15 minutes
Mid week: fix high severity and quick wins (redirects, headers, DNS)
Friday: run a quick validation scan and close the loop

How Barrion helps with continuous monitoring

Barrion automates the checks in this guide and keeps them running on a schedule. It watches HTTPS redirects, HSTS, TLS versions and ciphers, security headers, frontend package vulnerabilities, and more. You get alerts when new security issues are detected, so that you can take quick action to secure your application and users.

Barrion focuses on signal. It reports only material changes and verified issues so your team can spend time on fixes rather than sorting through noise. Set it up once, and keep your public surface healthy over time.

Conclusion

Security monitoring is about catching drift before users or attackers notice, and it needs to run continuously. Establish automated checks for HTTPS, headers, TLS, APIs, and DNS, and review a short weekly report. Keep the loop tight: detect, fix, verify.

Set up continuous monitoring in the Barrion dashboard, or start with quick spot checks using the Security Headers Test and the TLS test.