Information communication systems are an important component in most of today's enterprises. Due to the increasing number of devices that are connected in information communication systems, maintenance and security are becoming increasingly difficult. In my graduation thesis, I introduced systems for managing security information and events (SIEM), how they work and how they differ from log managers and IDS/IPS systems. I've checked existing commercial, free and open-source SIEM systems on the market. Then I implemented the SIEM system using only open-source components and evaluated it through use cases.