How to add Strict-Transport-Security on AWS CloudFront

Last updated November 11, 2026 · Reviewed by a CISSP-certified security practitioner

To add Strict-Transport-Security on AWS CloudFront, set the header in Response headers policy with the value max-age=63072000; includeSubDomains; preload. Forces browsers to only use HTTPS for your domain. Attach the policy to the distribution's cache behavior and wait for deployment. Then confirm it with curl -I or a free FixSecurityHeaders scan.

What does Strict-Transport-Security do?

HSTS tells the browser to always connect over HTTPS for a set time, even if someone types http:// or clicks an old link.

Risk if missing: Without it, the first request can be downgraded to plain HTTP, letting attackers on public Wi‑Fi intercept or rewrite traffic (SSL stripping).

What is the AWS CloudFront configuration?

Add this to Response headers policy:

Response headers policy

// aws cloudfront create-response-headers-policy --response-headers-policy-config file://policy.json
{
  "Name": "fixsecurityheaders-policy",
  "SecurityHeadersConfig": {
    "StrictTransportSecurity": {
      "Override": true,
      "AccessControlMaxAgeSec": 63072000,
      "IncludeSubdomains": true,
      "Preload": true
    }
  },
  "CustomHeadersConfig": {
    "Quantity": 0,
    "Items": []
  }
}

How do I add it step by step?

Open Response headers policy.
Paste the Strict-Transport-Security configuration shown below.
Attach the policy to the distribution's cache behavior and wait for deployment.
Run curl -I https://yourdomain.com and look for the strict-transport-security line.
Scan your site on FixSecurityHeaders to confirm the grade improved.

How do I verify it worked?

terminal

curl -sI https://yourdomain.com | grep -i "strict-transport-security"
# expected:
# strict-transport-security: max-age=63072000; includeSubDomains; preload

Check your site now

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What are the common mistakes?

The preload directive is hard to undo: removal from browser preload lists takes months.
includeSubDomains breaks any subdomain that still serves plain HTTP. Audit subdomains first.
Start with a short max-age (e.g. 300) and ramp up to 1–2 years once verified.
Browsers ignore HSTS sent over plain HTTP; it must be sent on the HTTPS response.
AWS provides a managed SecurityHeadersPolicy, but a custom policy lets you set CSP.
Enable Override so origin headers don't win.

Quick reference

Header	`Strict-Transport-Security`
Recommended value	`max-age=63072000; includeSubDomains; preload`
Stack	AWS CloudFront
Where	Response headers policy
Compliance	PCI DSS 4.0 4.2.1, NIST 800-171 3.13.8, CMMC SC.L2-3.13.8, OWASP ASVS V14.4.5, SOC 2 CC6.7

FAQ

What value should I use for Strict-Transport-Security?

A safe default is max-age=63072000; includeSubDomains; preload. The preload directive is hard to undo: removal from browser preload lists takes months.

Why isn't Strict-Transport-Security showing up on AWS CloudFront?

AWS provides a managed SecurityHeadersPolicy, but a custom policy lets you set CSP. Also clear any CDN or page cache, and check you edited the config that actually serves your domain.

Does Strict-Transport-Security affect SEO or performance?

No measurable performance cost — it's a few bytes per response. It doesn't affect rankings directly, but a misconfigured policy can break page resources, so test before enforcing.

Which compliance frameworks reference Strict-Transport-Security?

PCI DSS 4.0 4.2.1, NIST 800-171 3.13.8, CMMC SC.L2-3.13.8, OWASP ASVS V14.4.5, SOC 2 CC6.7.