The ERP systems have rapidly increasing role for the success of modern business. They are subject of rapid development process and rapidly spreading with increasing rate. In now days the typical ERP system has a much better functionalities than its predecessors and also relays on complex it infrastructure, frequently combining a wide set of IT technologies. Security of the ERP system is an important aspect of the entire system and must be properly maintained in order to achieve reliable and secure operation of the entire system. The security of an ERP system should not be regarded as a summary of the security of its components, but as a complex ecosystem comprised of multiple different layers, which also have a complex dependencies and relations between each other. There are also the processes of user identity and rights management that are a considered as an integral part of the overall security. Once configured, the security of the ERP systems could not be regarded as constant but evolves along with the challenges caused by increased numbers, severity and complexity of security threats present into the digital world. In order to mitigate the effects of such threats the security ecosystem of an ERP solution and its components should be a subject of regular audit and reviews to be able to be maintained at sufficient level.