This talk will cover the current state of .NET security/exploitation, using real-world examples of application-level vulnerabilities to framework bugs. Additionally, I will .NET security features and how to bypass, including bypassing strong-name signing including the GAC. Then, I will provide a short demo on how to modify the behavior of the .NET framework through DLL byte patching. Finally I will discuss defensive programming practices which can be used to guard against .NET vulnerabilities.