How SSH Works—and How It Breaks: A Practical Guide to Secure Remote Access

Introduction SSH (Secure Shell) is a cornerstone of modern computing. It’s no exaggeration to say that almost every software engineer and IT administrator has used an SSH client to manage a remote machine at some point of their careers. This protocol has been around since 1995 and it remains the gold standard of secure shell access. SSH provides encrypted tunnels over insecure networks, allowing secure access to remote machines. While the protocol itself is very robust and mature, its security ultimately depends on how it is used. Misconfigurations, inexperience and lack of knowledge can be an open door for attackers. And I’m speaking from experience. I've used SSH in insecure ways in the past, mainly because I didn’t fully understand how to protect my systems and applications correctly. In this series of three parts, we will explore how SSH can be misused, how attackers exploit common pitfalls, and how to avoid them. In the first part, we’ll discuss why you shouldn’t blindly trust the