As part of extensive research about rootkits, a number of tools and cases were developed to demonstrate changes that can be performed on systems running on a compiler in runtime. The research was performed on a number of common platforms, such as .NET and JAVA, but the same methods can be used generically for other systems too. As a part of the project, lectures and demonstrations were given and a book titled Managed Code Rootkits was written on the subject. The book contains examples of uses, both in context of security faults the technique enables and in the context of information security, creating a rootkit for the framework that hardens the running software during runtime.