SSH, key management, and jump boxes
Using SSH for remote management of Linux based operating systems is so ubiquitous that it deserves special consideration. SSH on its own is efficient and very secure, but it is well known and generally exposes such extreme functionality in our systems that it is often the target a focused attacks. We cannot be complacent in the use of SSH, especially if exposed to the Internet, as the risks are simply too high.
When using SSH we have almost a laundry list of ways that it can be secured. We will touch on several of these and how they work together to make SSH extremely difficult to compromise. SSH on Linux is provided via OpenSSH which is mature and battle tested and receives more scrutiny than almost any software package made. SSH starts as an already very harded package from most perspectives.
Our first tool for securing SSH is to consider completely removing password-based access to it in favor of using keys. Keys are fast and efficient allowing...