What is HSTS?
HSTS (HTTP Strict Transport Security) is a security protocol developed as a response to the need to increase the protection of data sent over the Internet. Its main purpose is to force the use of an encrypted HTTPS connection between the user's browser and the server, even if a website address was entered or a link was clicked using HTTP only.
By implementing HSTS, websites can prevent attacks that involve intercepting and modifying data sent over an unsecured connection. This mechanism, by adding a special header to the HTTP response, informs the browser that only HTTPS should be used for future requests to a given website. This way, even if the user tries to connect using an unencrypted HTTP connection, the browser will automatically redirect the query to a secure version of the page.
HSTS is therefore an important element of website security, ensuring that all data transferred between the website and its users is always encrypted and protected against unauthorized access.
How does HSTS work?
The HSTS mechanism works on the principle of communication between the server and the user's web browser, aimed at ensuring that all future connections to a given website will take place only via the secure HTTPS protocol. In practice, when a user visits a website using HSTS for the first time, the server sends a special HTTP response header to his browser, which activates the HSTS mechanism for the given domain.
This header, known as Strict-Transport-Security, contains information specifying how long the browser should remember that the page can only be accessed via HTTPS. This period is referred to as the "duration" and may vary between parties.
From the moment it receives this header, the browser will automatically redirect all unencrypted HTTP connection attempts to an encrypted HTTPS connection, even if the user enters an HTTP-only page address or clicks on a link to the HTTP version of the page.
Thanks to this, HSTS effectively eliminates the risk of "man-in-the-middle" attacks, where an attacker can intercept and modify transmitted data over an unsecured connection. This mechanism provides an additional layer of protection, operating transparently for the user and not requiring any additional actions or changes to browser settings.
Examples of websites using HSTS
The introduction of the HSTS mechanism has become a common practice among many popular websites that place particular emphasis on the security of their users' data. Below are some examples of well-known websites that have decided to implement HSTS, thus ensuring a higher level of protection for online communications.
- Google: As one of the leading technology companies, Google has implemented HSTS on many of its platforms, including Search, Gmail, and YouTube, to ensure secure communications for its users.
- Facebook: The social networking site, known for its attention to privacy and data security, also uses HSTS, thus preventing the interception and manipulation of data sent between users and Facebook servers.
- X (Twitter): Microblogging platform X uses HSTS to secure its users' connections, thus protecting against the possibility of interception of private messages and other sensitive information.
- PayPal: As a financial transaction processing service, PayPal is particularly concerned about the security of connections, using HSTS to protect its customers' financial data.
- Dropbox: The Dropbox cloud storage service also implements HSTS, increasing the security of data transfers between user devices and the service's servers.
The implementation of HSTS by these and many other services highlights the importance of this mechanism in building a safer Internet. Thanks to HSTS, users can be sure that their data is protected against potential attacks and unauthorized access, which is especially important in the era of growing cyber threats.
Advantages of using HSTS
Implementing HSTS on a website brings a number of benefits that significantly increase the level of security of data transmitted between the server and users. Here are the most important advantages of using HSTS:
- Increased security: HSTS effectively prevents man-in-the-middle attacks that can occur when data is transmitted over insecure HTTP connections. By enforcing all connections to be encrypted using HTTPS, HSTS minimizes the risk of data interception and manipulation.
- Automatic redirection to HTTPS: With HSTS, the browser automatically redirects all HTTP requests to secure HTTPS connections, even if the user enters the website address using HTTP. This eliminates the need to manually enter redirections at the server level.
- Protection against downgrade attacks: HSTS protects against attacks that attempt to force the use of a less secure connection (e.g. HTTP instead of HTTPS), which can be used to intercept data.
- Improving user trust: Websites using HSTS can be perceived by users as more trusted and secure, which translates into positive experiences and greater trust in the brand or website.
- Better performance: Although data encryption on HTTPS connections requires slightly more resources than unencrypted connections, automatic redirection to HTTPS eliminates the need for additional requests to the server to redirect to a secure version of the page, which can speed up page loading.
- Browser support: Most modern web browsers support HSTS, which means that the benefits of its implementation are available to a wide range of users.
The rest of the article, due to its topic, is intended for more technical people. If you do not manage the website yourself, I recommend sharing the article with your technical department.
Inclusion of the site in the HSTS preload list
An HSTS preload list is a collection of domains that are preloaded in web browsers as sites that require an HTTPS connection. Including your site on this list is a strong safeguard because it ensures that users only connect to your site through a secure connection, even the first time they visit. Here's how you can do it:
1. Meeting the registry requirements
Before starting the process, make sure your site meets all the requirements to be included in the preload list, including:
- Has a valid SSL certificate,
- All requests are redirected to HTTPS (including subdomains),
- It has the Strict-Transport-Security header set with the max-age parameter of at least 31536000 seconds (1 year) and the includeSubDomains and preload flags.
2. Testing the configuration
Before submitting your site, use online tools such as Qualys SSL Labs or HSTS Preload List Submission to test that HSTS is properly configured on your site. These tools will check that the HSTS headers are set correctly and that the site meets all criteria.
3. Site Report
Once you have confirmed that your site meets all the requirements, you can submit it for inclusion in the preload list using the official HSTS Preload website. Enter your website address and follow the instructions on the page.
4. Waiting patiently
Once submitted, your site will be reviewed by the HSTS preload list management team. This process may take several weeks or months. After successful review and approval, your site will be added to the next preload list update that will be rolled out to new browser versions.
5. Monitoring and maintenance
Once you have added your site to the preload list, it is important to continue monitoring and maintaining the site's security configuration, including SSL certificates and HSTS settings. Configuration changes or certificate expiration may impact the availability of the site to users.
Remember that the decision to add a site to the HSTS preload list is a serious commitment and should be carefully considered. Submitting a site to the preload list is irreversible without contacting the browser team directly to remove the domain from the list, which can be a time-consuming process.
Possible threats
Implementing HTTP Strict Transport Security significantly strengthens website security by enforcing the use of an encrypted HTTPS connection. However, like any technology, HSTS may involve some risks that are worth considering before implementing it:
- Difficulty in reversing decisions: Once HSTS is activated for a domain and added to the preload list, the process of deleting it is complicated and time-consuming. Domains in the preload list are built directly into browsers, so even removing the HSTS header from the server will not remove the domain from the preload list in users' browsers.
- Issues with insecure subdomains: If HSTS is enabled with the includeSubDomains directive, all subdomains must also support HTTPS. This can be a problem for subdomains that are not yet ready to switch to HTTPS, leading to connection errors and website unavailability.
- Configuration errors: Incorrect HSTS configuration may result in unintentional blocking of access to the site. For example, too long a duration (max-age) can cause configuration errors to have long-lasting effects on users, preventing them from accessing the page.
- Certification Requirements: HSTS requires a valid SSL/TLS certificate, which means additional obligations to obtain and renew it. An outdated or incorrectly configured certificate may make the website unavailable to users.
- HSTS hijacking attacks: Although HSTS makes man-in-the-middle attacks much more difficult, attacks that use HSTS to intercept a connection before it is encrypted are possible under certain conditions. This, however, requires more advanced techniques and is less common than standard man-in-the-middle attacks.
However, the implementation of HSTS is still an important step towards increasing website security and protecting user data. However, it is important to carefully consider all aspects before implementation, understand the potential threats and take appropriate countermeasures to minimize the risks associated with the use of HSTS.
Summary
HSTS is a very important and advanced security protocol that increases the protection of data transmitted online by enforcing the use of an encrypted HTTPS connection. This addresses the limitations of HTTPS itself, as HSTS automatically redirects any HTTP connection attempts to secure HTTPS, even if the user unknowingly tries to use an insecure connection. This feature is an important step in preventing man-in-the-middle attacks by protecting user data from interception and manipulation.
The implementation of HSTS is currently a standard among many popular websites that prioritize the security of their users' data, including giants such as Google, Facebook, and PayPal. The benefits of HSTS include not only increased security through data encryption, but also improved user trust and website performance. While HSTS brings many benefits, it is important to take a conscious approach to its implementation, given potential challenges such as difficulty in reversing deployment decisions or managing unsecured subdomains.
Frequently Asked Questions
What is HSTS?
HSTS (HTTP Strict Transport Security) is a security policy that forces browsers to use HTTPS encrypted connections when accessing a website. This helps protect against man-in-the-middle attacks.
Why should I use HSTS?
Using HSTS increases the security of user data by ensuring that all data transferred between the user and the website is encrypted. As a result, information such as login details, personal information and credit card details are better protected.
How does HSTS affect SEO?
Google prefers secure sites that use HTTPS, which can have a positive impact on search rankings. Implementing HSTS, as an additional security measure, may help to improve your website's position in search results.
Does HSTS affect website performance?
The introduction of HSTS should not negatively impact the website's performance. Although HTTPS connections require a small amount of additional processing power to encrypt data, the security benefits far outweigh this minimal cost.
How can I check if my website uses HSTS?
You can use SSL security testing tools like SSL Labs, which will check whether your site properly implements HSTS and other security aspects of HTTPS connections.
Can I remove HSTS from my site?
You can remove HSTS from your site by updating your server configuration and removing the Strict-Transport-Security header. However, for users who have already visited your site, the HSTS setting will remain in effect until the max-age value expires, unless they clear their browser cache.
What happens if my SSL certificate expires?
If your SSL certificate expires, users visiting your site with HSTS enabled may encounter connection errors because the browser will force an HTTPS connection, which cannot be securely established without a valid certificate. It's important to keep your SSL certificates up to date.
Adam Naworski
