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What is an example of a session fixation attack?
A typical scenario involves the attacker prompting their victim into clicking on a link which directs them to sign in, while also supplying a Session ID. The server accepts the Session ID, and populates the session with information about the authenticated user.
How session fixation is different from Session Hijacking?
In the session hijacking attack, the attacker attempts to steal the ID of a victim’s session after the user logs in. In the session fixation attack, the attacker already has access to a valid session and tries to force the victim to use that particular session for his or her own purposes.
What is session fixation in security?
Session Fixation is an attack that permits an attacker to hijack a valid user session. The session fixation attack is not a class of Session Hijacking, which steals the established session between the client and the Web Server after the user logs in.
What is weak session ID attack?
Weak session IDs can expose your users to having their session hijacked. If your session IDs are picked from a small range of values, an attacker only needs to probe randomly chosen session IDs until they find a match.
How can I secure my session ID?
The recommended session ID must have a length of 128 bits or 16 bytes. A good pseudorandom number generator (PNRG) is recommended to generate entropy, usually 50% of ID length. Cookies are ideal because they are sent with every request and can be secured easily.
What is session fixation and how does it work?
Session Fixation is an attack that permits an attacker to hijack a valid user session. The attack explores a limitation in the way the web application manages the session ID, more specifically the vulnerable web application. When authenticating a user, it doesn’t assign a new session ID, making it possible to use an existent session ID.
How is the session token sent to the victim?
• Session token in the URL argument: The Session ID is sent to the victim in a hyperlink and the victim accesses the site through the malicious URL. • Session token in a hidden form field: In this method, the victim must be tricked to authenticate in the target Web Server, using a login form developed for the attacker.
How does the attacker fix the session ID?
This method explores the server response to fix the Session ID in the victim’s browser. Including the parameter Set-Cookie in the HTTP header response, the attacker is able to insert the value of Session ID in the cookie and sends it to the victim’s browser.
How can I Predict a valid session ID?
Predictable sessions token ID. Many web servers use a custom algorithm or predefined pattern to generate session IDs. The greater the predictability of a session token, the weaker it is and the easier it is to predict. If the attacker can capture several IDs and analyze the pattern, he may be able to predict a valid session ID.