Security of Information Systems is a very important but also an expensive security process for an organization or corporation. Often we encounter misunderstanding and disagreement of the top management with the idea of implementing this kind of system in the business process. One of the reasons is the low awareness of the leading people of a corporation or organization about the devastating consequences of unauthorized access to data, which will only be a matter of time and how strength it will hit the company or organization's business, consequences and the damage that cyber criminals will be creating. With proper implementation of such protection systems, the possibility of attack will certainly not be reduced to zero, but we will manage to notice them in a large amount through time, and react according to the protocol that the system imposes in emergencies. With the spreading of the Internet world wide, threats have increased and one of the main culprits is just an insufficiently trained employee. With its negligence and insufficient attention, it is one of the main culprits of hacker attacks on companies. Therefore, if we want to install a security system, it is very important to work on all aspects of security and to timely and properly trace employees, to raise awareness of the most common hacker attacks and how to protect them on the Internet. not following only one of the above mentioned segments, very expensive system security in a company or organization will be only throwing money and failure.