Guide to HTTP Strict Transport Security (HSTS)
What is HTTP Strict Transport Security (HSTS)?
HTTP Strict Transport Security (HSTS) is a web security policy mechanism that helps to protect websites against man-in-the-middle attacks such as protocol downgrade attacks and cookie hijacking. It allows web servers to declare that web browsers (or other complying user agents) should only interact with it using secure HTTPS connections, and never via the insecure HTTP protocol.
Why is HSTS important?
HSTS is crucial for web security as it ensures the security of sensitive information as it travels across the web, preventing data theft and tampering.
How does HSTS work?
HSTS works by including a special response header named 'Strict-Transport-Security' for all HTTP responses made by a website. A HSTS Host, after receiving this HTTP response, will remember to always access the website via HTTPS, even if it was requested as HTTP.
Exam Tips: Answering Questions on HTTP Strict Transport Security
In an exam, remember the following about HSTS:
- HSTS is not backwards compatible with HTTP. It only works with HTTPS.
- If a website using HSTS fails to provide an accurate certificate, the site will be unreachable.
- HSTS headers are only respected when they are served over HTTPS.
- Implementing the HSTS policy through headers is a smart countermeasure to protocol downgrade attacks.
Remember points like these, and be prepared to answer both definition and situational questions about HSTS' role and application within web security.