SSH | Not Just a Command Line Utility

2021-02-22
1 min read

WTF is SSH?

If you reside within the information security community, you have almost definitely used the standard SSH utility, ssh. If you are not familiar with it, the Secure SHell has a variety of features that can be highly useful. Ad-hoc network tunelling proves to be substantially useful in a variety of situations. Furthermore, the ability to transfer files or execute commands on a whim makes this an indisputably powerful utility.

How does SSH work?

The standard client is implemented primarily using a library aptly named libssh.

libssh provides a variety of functions, procedures, and structures that facilitate the establishment of secure, encrypted channels and the connections that they reside on. Proper assembly of these functions, procedures and structures in an implementation can provide reliable, secure access to controlled resources.

The primary component of an SSH transaction is a session. A client creates a session and establishes a TCP connection to the target server for the session to communicate through. It then establishes a channel through the session.