OWASP Tutorial – Testing For HTTP Strict Transport Security Vulnerability

Testing For HTTP Strict Transport Security Vulnerability

The HTTP Strict Transport Security (HSTS) header is a mechanism that websites have to communicate to the web browsers that all traffic exchanged with a given domain must always be sent over https, this will help protect the information from being passed over unencrypted requests.

Considering the importance of this security measure it is important to verify that the website is using this HTTP header, in order to ensure that all the data travels encrypted from the web browser to the server.
The HTTP Strict Transport Security (HSTS) feature lets a web application to inform the browser, through the use of a special response header, that it should never establish a connection to the specified domain servers using HTTP. Instead, it should automatically establish all connection requests to access the site through HTTPS.

The HTTP strict transport security header uses two directives:

• max-age: to indicate the number of seconds that the browser should automatically convert all HTTP requests to HTTPS.
  
• includeSubDomains: to indicate that all web application’s sub-domains must use HTTPS.
  

Here’s an example of the HSTS header implementation:

Strict-Transport-Security: max-age=60000; includeSubDomains

The use of this header by web applications must be checked to find if the following security issues could be produced:

Attackers sniffing the network traffic and accessing the information transferred through an unencrypted channel.

Attackers exploiting a man in the middle attack because of the problem of accepting certificates that are not trusted.

Users who mistakenly entered an address in the browser putting HTTP instead of HTTPS, or users who click on a link in a web application which mistakenly indicated the HTTP protocol.

Request:

Response:

Conclusion

HTTP Strict Transport Security (HSTS) is a powerful key to provide protection against man in the middle attack and many other attacks. We recommend providing awareness of HSTS early in web application development lifecycle.