In my last post (Session Fixation & Forms Authentication Token Termination in ASP.NET), I talked about ways to mitigate two types of session related vulnerabilities in an ASP.NET MVC 4 application. One of these vulnerabilities is also present in many WCF web services. In one mode of operation, WCF web services can authenticate users and issue forms authentication cookies. Since this token contains an encrypted set of values and resides only on the client-side, the server cannot choose to invalidated that token and end a user’s authenticated session. This allows attackers to continue using stolen tokens, even after the user logs out.
Continue reading this article on the Security PS Blog: http://blog.securityps.com/2013/07/forms-authentication-token-termination.html