This is a multi-part blog post about port scanning. In this post we're going to cover port scan theory. In the next post in this series we'll look at the practical parts of port scanning. It might seem a little dry in places, but stick with it as it's knowledge you're almost certainly going to be tested on in any professional exam. If it's not in your exam, you're in the wrong class.
Every now and again when pentesting you come across something that doesn't quite seem right. You can't always put your finger on it, it's just a little... off. Whether it's a code execution bug that's a little too easy to exploit, or the demo user account that looks like someone forgot to remove, sometimes vulnerabilities just seem as though they were deliberately placed there, even if it's for legitimate purposes. These bugs are commonly known as backdoors, and in this post I'll go through the steps in detecting some common types of backdoor from the network.
At the inaugural 44CON Cybersecurity I conducted a workshop on career planning. Career planning is something people tend to do at school, college or university but rarely as adults. Many people experience career planning through a disinterested and irrelevant prism, so it's not surprising they find it dull.