---
title: "WEB-HDR-001 Missing HTTP Strict Transport Security (HSTS)"
canonical: https://openvapt.com/checks/WEB-HDR-001.html
html: https://openvapt.com/checks/WEB-HDR-001.html
site: OpenVAPT, https://openvapt.com/
license: OpenVAPT Source-Available Licence 1.3, https://openvapt.com/legal/licence-text.html
modified: 2026-10-14
version: 0.1.0-alpha.6
---

# WEB-HDR-001 Missing HTTP Strict Transport Security (HSTS)

Checks that HTTPS sites tell browsers to always use HTTPS, for at least six months.

- Domain: Web Apps
- Severity: Medium
- Control category: Web Application Security
- Fix effort: low
- CVSS v3.1 vector: `CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N`
- CIS Controls v8: 16.7
- NIST CSF 2.0: PR.PS-01
- CWE: CWE-319, CWE-523
- OWASP Top 10 2021: A05:2021
- OWASP ASVS 4.0.3: 14.4.5
- OWASP WSTG v4.2: WSTG-CONF-07
- NIST SP 800-53 Rev. 5: SC-8

## Why It Matters

Without HSTS, the first visit or any typed http:// link can be intercepted and downgraded to plain HTTP (SSL stripping) on public Wi-Fi.

## How It Detects

Reads the Strict-Transport-Security header from each HTTPS site's home page, including a redirect response, because browsers honour HSTS on any HTTPS response. Plain HTTP responses are not evaluated. Missing, or max-age below 15552000 seconds (180 days), fails.

## How to Fix

Apache: Header always set Strict-Transport-Security "max-age=31536000; includeSubDomains" . nginx: add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always; . Only add 'preload' once every subdomain supports HTTPS.

## How to Verify

```
curl -sI https://<site>/ | grep -i strict-transport-security
```

## Learn the Theory

- [P4 TLS, Certificates and HTTPS](https://openvapt.com/academy/p4.md)
- [A8 Tracing Findings to Security Requirements](https://openvapt.com/academy/a8.md)

## References

- [RFC 6797, HTTP Strict Transport Security](https://www.rfc-editor.org/rfc/rfc6797.html)
- [OWASP HTTP Headers Cheat Sheet](https://cheatsheetseries.owasp.org/cheatsheets/HTTP_Headers_Cheat_Sheet.html)
- [MDN Web Docs, Strict-Transport-Security](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Strict-Transport-Security)

## Source Code

https://github.com/OpenVAPT/openvapt/blob/574f7f3333c44b75a3c649e2d93a76d507f75adf/internal/checks/web/headers.go

Run it: `openvapt scan --only WEB-HDR-001`. Read it offline: `openvapt explain WEB-HDR-001`.

---

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