Abstract: Cyber security is the biggest treat as well as opportunity in the contemporary world. The exponential rise in the volume, veracity and variety of cyber-crime cases are matched with a significant increase in cyber security professionals. Cyber Security is a discipline which involves security of all its related resources. I have given a brief evaluation of cyber security and cyber crimes by reviewing some articles and research papers about cyber security and cyber-crime.Cyber-crime, or Computer oriented crime, is a crime that involves a computer and a network. The computer may be used in the commission of a crime, or it may be the target. Crimes that done against any person or an individual to gain the profit or to harm the reputation of the person or cause physical or mental harm to the person directly or indirectly, using modern technology i.e. Internet and mobile phones etc. And cyber security is the term used to protect a system from the theft and damage of their hardware,software and information as well as disruption and misdirection of a service. Keyword:hacking, hacker, threats,vulnerability, exploits, server, crime against person, crime against property, crime against government, internet-basedthefts, sections etc.