What security measures should be implemented in PHP applications to protect against session hijacking or reactivation of old sessions?

Session hijacking can be prevented by implementing secure session handling techniques in PHP applications. To protect against session hijacking or reactivation of old sessions, developers should use session_regenerate_id() function to generate a new session ID whenever a user's privilege level changes or sensitive actions are performed. This helps to mitigate the risk of session fixation attacks and ensures that old session IDs cannot be reused by attackers.

// Start or resume a session
session_start();

// Regenerate session ID to prevent session fixation attacks
session_regenerate_id(true);