Adding custom NASL plugins to Tenable Nessus. Making custom NASL scripts (plugins) for Nessus is a pretty complicated process. Basically, NASL (Nessus Attack Scripting Language) is an internal instrument of Tenable and it seem that they are not really interested in sharing it with the community. The only publicly available official documentation, NASL Reference Guide and NASL2 reference manual, was written at least 13 years ago. Certainly many things changed since then in the actual product.
However, it’s still possible to add custom NASL scripts into the plugin set of your Nessus server. Let’s see how to do it. Everything was tested in the latest Nessus 8.