# Session Fixation ## **Part 1: Session fixation identification** Navigate to `oredirect.htb.net`. You will come across a URL of the below format: `http://oredirect.htb.net/?redirect_uri=/complete.html&token=` Using Web Developer Tools (Shift+Ctrl+I in the case of Firefox), notice that the application uses a session cookie named `PHPSESSID` and that the cookie's value is the same as the `token` parameter's value on the URL.
If any value or a valid session identifier specified in the `token` parameter on the URL is propagated to the `PHPSESSID` cookie's value, we are probably dealing with a session fixation vulnerability. Let us see if that is the case, as follows. ## **Part 2: Session fixation exploitation attempt** Open a `New Private Window` and navigate to `http://oredirect.htb.net/?redirect_uri=/complete.html&token=IControlThisCookie` Using Web Developer Tools (Shift+Ctrl+I in the case of Firefox), notice that the `PHPSESSID` cookie's value is `IControlThisCookie`
We are dealing with a Session Fixation vulnerability. An attacker could send a URL similar to the above to a victim. If the victim logs into the application, the attacker could easily hijack their session since the session identifier is already known (the attacker fixated it). > **Note**: Another way of identifying this is via blindly putting the session identifier name and value in the URL and then refreshing. For example, suppose we are looking into `http://insecure.exampleapp.com/login` for session fixation bugs, and the session identifier being used is a cookie named `PHPSESSID`. To test for session fixation, we could try the following `http://insecure.exampleapp.com/login?PHPSESSID=AttackerSpecifiedCookieValue` and see if the specified cookie value is propagated to the application (as we did in this section's lab exercise).
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