In a new tutorial on PHPBuilder.com Marc Plotz takes a look at the security of your sessions and how to protect them from would-be data thieves.
Sessions are a very complicated part of PHP, and it is no surprise that the smarter website attacks are carried out on sessions. Most of these attacks involve one user impersonating another, or, more to the point, "hijacking" the other user's session data. As most experienced developers know, exploiting session data is an easy way into most low-to-medium security level websites--after all, that is how most website login systems work.
He looks at a few methods the hacker could use to get at your session data - session fixation, capturing and predicting where the values could be set so you can gain access.