Website Security Playbook: From HTTPS to Zero Trust
Written by on Thursday, September 18th, 2025
The Definitive Guide to Website Security: HTTPS, TLS, HSTS, CSP, SRI, WAFs, DDoS Protection and Zero-Trust Hosting
Modern websites face automated bots, supply-chain tampering, credential stuffing, and volumetric attacks. A resilient defense layers transport security, browser controls, network shields, and identity-aware infrastructure. Below is a practical roadmap that pairs concepts with field-tested examples.
HTTPS and Modern TLS
Always serve every page over HTTPS with TLS 1.2+ (prefer TLS 1.3), enable forward secrecy, and turn on OCSP stapling and HTTP/2 or HTTP/3. Strong ciphers (AES-GCM or ChaCha20-Poly1305) and automatic certificate renewal reduce misconfigurations.
Example: A regional retailer upgraded to TLS 1.3 and enforced HTTPS; browser mixed-content errors vanished, cart abandonment fell, and a credential-snooping Wi-Fi attack failed because plaintext was never exposed.
HSTS: No Going Back to HTTP
HTTP Strict Transport Security forces browsers to use HTTPS, blocking downgrade and cookie hijacking via plaintext. Deploy a long max-age (e.g., 31536000), includeSubDomains, and consider preload once confident.
Example: A SaaS dashboard previously vulnerable to user-initiated “http://” bookmarks eliminated that risk after HSTS; support tickets about “login not secure” dropped to zero.
CSP: Contain What the Browser Executes
Content Security Policy limits where resources load from and which scripts may run, throttling cross-site scripting. Start with default-src 'self', add nonces for inline scripts (script-src 'self' 'nonce-...'), and block legacy plugins with object-src 'none'. Use upgrade-insecure-requests and reporting endpoints to iterate safely.
Example: A marketing pixel was compromised upstream; CSP blocked the injected inline payload, and the team received reports to rotate the tag.
SRI: Trust but Verify Third-Party Assets
Subresource Integrity adds a cryptographic hash to external scripts/styles so tampering breaks loading. Pair SRI with CSP’s allowlists to secure CDN assets without freezing agility.
Example: A popular icon library on a CDN was altered for 20 minutes; SRI prevented execution while unaffected mirrors loaded normally.
WAFs and DDoS Protection
Web Application Firewalls detect injection, file inclusion, and deserialization attacks; advanced WAFs add bot management, behavioral anomalies, and positive security models. For DDoS, combine anycast networks, on-demand scrubbing, rate limiting, and L7 request validation to withstand volumetric and application-layer floods.
Example: During a product launch, a burst of L7 traffic was absorbed by a CDN/WAF edge with adaptive rate limits, preserving checkout latency.
Zero-Trust Hosting
Assume breach: enforce identity-aware access, least-privilege IAM, micro-segmentation, mTLS between services, short-lived credentials, and centralized secrets. Use service meshes and policy engines to codify who can talk to what—and why.
Example: A staging site moved behind an identity proxy with per-branch environments; leaked static credentials ceased to matter, and partner access became auditable.
Actionable Setup Checklist
- Redirect all traffic to HTTPS; enable TLS 1.3 and automatic cert renewals.
- Set HSTS with long max-age, includeSubDomains, and consider preload.
- Deploy CSP with nonces; iterate in report-only mode before enforcing.
- Add SRI to third-party JS/CSS; avoid wildcard CDNs without hashes.
- Front origin with a WAF/CDN; enable bot controls and L7 rate limits.
- Adopt zero-trust: mTLS, least privilege, short-lived tokens, secret manager.
- Continuously monitor, patch, and test with automated scanners and bug bounties.