In our previous article we dissected penetration testing techniques for IBM z/OS mainframes protected by the Resource Access Control Facility (RACF) security package. In this second part of our research, we delve deeper into RACF by examining its decision-making logic, database structure, and the interactions between the various entities in this subsystem. To facilitate offline analysis of the RACF database, we have developed our own utility, racfudit, which we will use to perform possible checks and evaluate RACF configuration security. As part of this research, we also outline the relationships between RACF entities (users, resources, and data sets) to identify potential privilege escalation paths for z/OS users. This material is provided solely for educational purposes and is intended…