Session Management

Session management is a fundamental aspect of web application security because HTTP is a stateless protocol. After a user authenticates, the application must create and maintain a session to track the user's identity across subsequent requests. This is typically achieved through session tokens stored in cookies, URL parameters, or request headers.

Secure session management requires attention to several critical areas. Session tokens must be generated using a cryptographically secure random number generator with sufficient entropy to prevent prediction or brute-force attacks. Tokens should be transmitted only over encrypted HTTPS connections and stored in cookies with the Secure, HttpOnly, and SameSite attributes set appropriately.

Common session management vulnerabilities include session fixation (where an attacker sets a known session ID before the user authenticates), session hijacking (where an attacker steals an active session token through XSS, network sniffing, or other means), and insufficient session expiration (where sessions remain valid long after they should have been invalidated).

Best practices include regenerating session IDs after authentication and privilege changes, implementing absolute and idle session timeouts, providing secure logout functionality that invalidates the session server-side, binding sessions to client characteristics such as IP address or user agent for additional verification, and maintaining server-side session state rather than relying solely on client-side tokens.