Identification of HSTS (HTTP Strict Transport Security) Misconfiguration

Identifying HTTP Strict Transport Security (HSTS) misconfigurations involves examining how HSTS headers are implemented and enforced within web applications. HSTS is a security mechanism that instructs web browsers to only interact with a website over HTTPS, reducing the risk of protocol downgrade attacks and man-in-the-middle attacks. Here's how you can identify HSTS misconfigurations:


  1. Reviewing HTTP Response Headers: Inspect the HTTP response headers returned by the server to see if the Strict-Transport-Security header is present. This header is used to enable HSTS.
  2. Checking HSTS Policy Settings: Verify the settings of the Strict-Transport-Security header to ensure they are configured correctly. Pay attention to the max-age directive, which specifies the duration (in seconds) for which the browser should enforce HTTPS.
  3. Testing HSTS Preload Status: Check if the website is included in the HSTS preload list maintained by browsers. Websites included in this list are hardcoded into browsers to always enforce HTTPS, providing an additional layer of protection.
  4. Analyzing HSTS Header Presence: Determine if the HSTS header is present on all secure endpoints of the website, including subdomains. HSTS should be enabled for the entire domain to prevent potential vulnerabilities.
  5. Testing for Header Overriding: Test if the HSTS header can be overridden by subsequent responses or by user-controllable input. Proper HSTS configuration should prevent header manipulation by attackers.
  6. Verifying HTTPS Redirection: Ensure that HTTP requests are automatically redirected to HTTPS to enforce the use of secure connections. HSTS should complement HTTPS redirection to provide comprehensive protection against downgrade attacks.


  • Example 1: During testing, a penetration tester discovers that the website does not include the Strict-Transport-Security header in its HTTP responses. This exposes the website to potential protocol downgrade attacks and SSL-stripping attacks.
  • Example 2: The tester finds that the website includes the Strict-Transport-Security header with a short max-age value (e.g., 3600 seconds). This short duration increases the risk of attackers being able to execute downgrade attacks once the HSTS policy expires.


  1. Enable HSTS: Configure the server to include the Strict-Transport-Security header in HTTP responses with a sufficiently long max-age value to enforce HTTPS connections.
  2. Include Subdomains: If applicable, include the includeSubDomains directive in the HSTS header to enforce HTTPS for all subdomains of the website.
  3. Preload Status: Submit the website to the HSTS preload list maintained by browsers to ensure that it is always accessed over HTTPS, even by users who have never visited the site before.
  4. Redirection to HTTPS: Implement automatic redirection from HTTP to HTTPS for all incoming requests to ensure that users always access the website securely.
  5. Regular Testing: Conduct regular security assessments to verify the effectiveness of HSTS implementation and to identify any misconfigurations or weaknesses.

By identifying and addressing HSTS misconfigurations, organizations can enhance the security of their web applications and protect users from potential security risks associated with insecure HTTP connections.