Security Intermediate

What is Security Headers?

HTTP response headers that instruct browsers to enable security features like XSS protection, framing prevention, and content type enforcement.

Essential security headers include Content-Security-Policy (control resource loading), X-Frame-Options (prevent clickjacking), X-Content-Type-Options: nosniff (prevent MIME sniffing), Strict-Transport-Security (force HTTPS), and Referrer-Policy (control referrer information).

Additional headers include Permissions-Policy (restrict browser features), X-XSS-Protection (legacy XSS filter), and Cross-Origin headers (CORP, COEP, COOP). Security headers are a crucial defense layer that requires no code changes — just server configuration.

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Related Terms

Input Validation

The process of verifying that user-supplied data meets expected formats, types, and ranges before processing it.

Session Hijacking

An attack where an adversary takes over a legitimate user session by stealing or predicting the session identifier.

An attack where malicious SQL code is inserted into application queries through user input to access or manipulate the database.

SIEM (Security Information and Event Management)

A platform that collects, correlates, and analyzes security events from across an organization to detect threats and incidents.

CORS (Cross-Origin Resource Sharing)

A browser security mechanism that controls which web domains can access resources from another domain via HTTP requests.

A regularly updated list of the ten most critical web application security risks, published by the Open Web Application Security Project.

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