The CA-TSS Facility Control Option must specify the sub option of MODE=FAIL.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-223957	TSS0-ES-000840	SV-223957r958808_rule		High

Description
Utilizing a whitelist provides a configuration management method for allowing the execution of only authorized software. Using only authorized software decreases risk by limiting the number of potential vulnerabilities. The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. Verification of white-listed software occurs prior to execution or at system startup. This requirement applies to operating system programs, functions, and services designed to manage system processes and configurations (e.g., group policies).

Description

Utilizing a whitelist provides a configuration management method for allowing the execution of only authorized software. Using only authorized software decreases risk by limiting the number of potential vulnerabilities. The organization must identify authorized software programs and permit execution of authorized software. The process used to identify software programs that are authorized to execute on organizational information systems is commonly referred to as whitelisting. Verification of white-listed software occurs prior to execution or at system startup. This requirement applies to operating system programs, functions, and services designed to manage system processes and configurations (e.g., group policies).

STIG	Date
IBM z/OS TSS Security Technical Implementation Guide	2024-06-24

Details

Check Text ( C-25630r516270_chk )
From the ISPF Command Shell enter: TSS MODIFY(FACILITY(ALL)) If the Facility Control Option does not specifies the sub option of "MODE=FAIL" for all facilities, this is a finding.

Fix Text (F-25618r516271_fix)
Evaluate the impact associated with implementation of the Facility Control Option MODE sub-option. Develop a plan of action to implement the Facility Control Option MODE sub-option setting to "MODE=FAIL" and proceed with the change.