What is Session Fixation?
Session fixation is a type of web security vulnerability that allows an attacker to hijack a user session by forcing them to use a specific session ID. It typically occurs when an attacker tricks a user into authenticating with a predetermined session ID, enabling the attacker to take control of the user's session once authenticated.
This attack exploits the way session identifiers are generated, retained, and validated in web applications. In a typical session fixation attack, the attacker may send a link containing a valid session ID to the target user. When the user clicks the link and logs in, they inadvertently authenticate with the attacker's session ID, thus giving the attacker access after the user's successful login.
To mitigate session fixation attacks, developers can implement several strategies. First, they should regenerate the session ID after a user logs in to ensure that the session ID is unique and unpredictable. Additionally, using secure cookies, enabling HTTP-only flags, and implementing proper session timeout policies can help protect against this threat. By following these practices, web applications can enhance their security and protect user sessions from being compromised.