Elevate

Enhanced Definition

In the context of IBM z/OS, to **elevate** refers to the act of increasing the privilege level of a program, task, or user to allow it to perform operations that are normally restricted. This is typically required for accessing sensitive system resources, executing privileged instructions, or bypassing standard security checks within the operating system.

Key Characteristics

- Privilege Levels: z/OS employs various privilege mechanisms, including APF-authorization (Authorized Program Facility), Supervisor State, Storage Key 0, and Program Properties Table (PPT) entries, which grant different degrees of system access.
- Controlled Access: Elevation is a highly controlled process, primarily managed by the Security Authorization Facility (SAF), often implemented by RACF (Resource Access Control Facility), which validates requests for privileged access.
- Methods of Elevation: Programs can be elevated by being loaded from an APF-authorized library, being defined in the PPT with specific attributes (e.g., PRIVILEGED, SYSTEM), or by executing an SVC (Supervisor Call) that transitions the system into a more privileged state.
- System Integrity: Elevation is crucial for maintaining system integrity, as it allows core operating system components and critical utilities to perform their functions while preventing unauthorized or malicious code from compromising the system.
- Security Implications: Improperly authorized or poorly coded elevated programs pose significant security risks, as they can bypass standard security controls and potentially compromise the entire system.

Use Cases

- System Utilities: Core z/OS utilities like IEBGENER, DFSMSdss, or IDCAMS often run APF-authorized to perform operations such as managing datasets, allocating storage, or manipulating system catalogs.
- Security Software: Security products like RACF require elevated privileges to manage user profiles, resource permissions, and system-wide security settings.
- Database Systems: Components of database management systems like DB2 or IMS may run with elevated privileges to manage buffer pools, access raw disk volumes, or interact directly with the operating system for performance and data integrity.
- System Monitoring Tools: Performance monitors and diagnostic tools often require elevated privileges to access system control blocks, trace system events, and gather comprehensive performance data.
- Installation and Maintenance: Installing or updating z/OS components or major subsystems frequently involves running programs that require elevated privileges to modify system libraries, link packs, or system configurations.

Related Concepts

Elevation is intrinsically linked to RACF/SAF, which governs who or what can be authorized to run with elevated privileges. It relies heavily on APF (Authorized Program Facility), where programs residing in APF -authorized libraries are trusted by the system. Programs running in Supervisor State or with Storage Key 0 have the highest level of privilege, allowing them to execute privileged instructions and access any storage. The Program Properties Table (PPT) is another mechanism to assign specific attributes, including privilege, to programs.

Best Practices:

Principle of Least Privilege: Grant only the minimum necessary privileges required for a program or user to perform its function, and only for the duration it is needed.
Strict APF Library Control: Maintain rigorous control over which libraries are APF -authorized and who can modify their contents. Unauthorized changes to APF libraries are a major security vulnerability.
Code Review and Testing: Thoroughly review and test all programs intended to run with elevated privileges to ensure they are robust, secure, and do not introduce vulnerabilities or instability.
Regular Audits: Conduct regular security audits of APF -authorized programs, libraries, and RACF profiles to identify and rectify any unauthorized access or configuration weaknesses.
Secure Coding Practices: When developing authorized programs, adhere to secure coding practices to prevent common vulnerabilities like buffer overflows or unauthorized data access, as these can have system-wide impact.