Introduction

Most of the security vulnerabilities being discovered utilize the same attack vectors. These attack vectors can be rewritten in each NASL (Nessus Attack Scripting Language) or can be written once using an include file that is referenced in different NASLs. The include files provided with the Nessus environment give an interface to protocols such as Server Message Block (SMB) and Remote Procedure Call (RPC) that are too complex to be written in a single NASL, or should not be written in more than one NASL file.

Extending NASL Using Include Files

The Nessus NASL language provides only the most basic needs for the tests written with it. This includes socket connectivity, string manipulation function, Nessus knowledge base accessibility, and so on.

Much of the functionality used by tests such as SMB, SSH (Secure Shell), and extended HTTP (Hypertext Transfer Protocol) connectivity were written externally using include files. This is due to two main reasons. First, building them within Nesuss's NASL language implementation would require the user wanting to change the functionality of any of the extended function to recompile the Nessus NASL interpreter. On the other hand, providing them through external include files minimizes the memory footprint of tests that do not require the extended functionality provided by these files.