In a z/OS operating system, a special security system is responsible for authenticating users and authorising them to access resources. RACF is often used for this. As a rule, the default configuration of RACF does not match the security requirements in the operational scenario at hand. The resources and z/OS system commands are protected using special classes in RACF, for example. If these classes are inadequately defined, it is possible for users to issue system commands that could degrade stable system operation in certain circumstances.