A while ago I decided the learn the basics of the Assembly language for my x64 processor. Assembly has a reputation for being difficult and elitist which is keeping many people from trying it out. But once you learn the basics, it is actually really simple. In fact, in many ways it is much simpler than other programming languages. Using Linux as our host system, we can make system calls to the kernel for many operations like reading and writing standard input/output and files. Also the x86 instruction set allows us to perform string operations and "loops" directly with a single instruction, condensing many common operations into just a few lines of code.
One important aspect in securing a Linux system is closing any open TCP ports which don't need to be publicly accessible. This reduces the attack surface that the system exposes for malicious actors. In case a service needs to be accessed only locally, a good practice is to bind it on the local loopback IP address (127.0.0.1).
Have you ever encountered a situation where the performance of your PHP script is not great, but you are not sure where the problem is? Then you try to guess and change some part blindly just to see if that would help?