A vulnerability is a weakness or flaw in a computer system, software application, network infrastructure or really any component of a computer/network environment that can be exploited.  Vulnerabilities are not just only within code, but it could be in a design flaw or misconfiguration or just bad security practices. 

When a vulnerability exists this provides an entry point for an attacker. When a vulnerability is exploited an attacker is able to gain unauthorized access. They might then be able to manipulate data on the systems, compromise other systems, disrupt operations and even plant a method for them to easily return (a backdoor). 

In this module we will learn how vulnerabilities are tracked, how to do a vulnerability scan and how to read the results.