Security fundamentals: threats, vulnerabilities, exploits, mitigation and user awareness

Security discussions use a few words with precise meanings, and the CCNA expects you to use them correctly. A vulnerability is a weakness in a system, such as unpatched software, a default password or an open management port. A threat is anything that could take advantage of a vulnerability to cause harm, such as an attacker, malware or even a flood. An exploit is the specific method or tool that actually takes advantage of a vulnerability. Risk is the likelihood that a threat will exploit a vulnerability combined with the impact if it does. Mitigation is any measure that reduces risk: removing the vulnerability, reducing the threat's chance of success or limiting the damage.