Hands on Hacking

Chapter 9Files and File Sharing

Every device, directory, and document (whether it be an image, audio, or text) on a UNIX-like system is represented by a file. These files are stored within a file system that contains permission models to identify who or what may access those files. It is imperative that you understand the way file systems work, especially with regard to permissions, as slight modifications to files can cause significant vulnerabilities to arise.

In this chapter, you will learn about file permissions and common protocols used for the sharing of files over networks. We're reviewing internal networks now, where you may have disparate hosts connected and needing to communicate with each other. We are no longer in the realm of just Linux—we're looking at proprietary, closed-source Microsoft technology too.

Imagine that you have breached the outer perimeter of a network through a virtual private network (VPN) server—perhaps using the techniques discussed in the previous chapter—and you can see internal hosts. It is likely that one of these hosts will be a file server, or some form of network-attached storage (NSA). We are no longer assessing publicly accessible hosts; rather, we are looking at hosts that are meant to be accessed internally, by employees only. When working for a client, you may find that the client wants you to take a look at the internal network regardless of whether any serious flaws were found in the external perimeter. Most businesses will share ...