The IBM z/VM SYSTEM CONFIG file must be configured to clear TDISK on IPL.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-237924	SRG-OS-000138-GPOS-00069	IBMZ-VM-000710	SV-237924r858980_rule	2022-08-31	2

Description
Preventing unauthorized information transfers mitigates the risk of information, including encrypted representations of information, produced by the actions of prior users/roles (or the actions of processes acting on behalf of prior users/roles) from being available to any current users/roles (or current processes) that obtain access to shared system resources (e.g., registers, main memory, hard disks) after those resources have been released back to information systems. The control of information in shared resources is also commonly referred to as object reuse and residual information protection. This requirement generally applies to the design of an information technology product, but it can also apply to the configuration of particular information system components that are, or use, such products. This can be verified by acceptance/validation processes in DoD or other government agencies. There may be shared resources with configurable protections (e.g., files in storage) that may be assessed on specific information system components.

Description

Preventing unauthorized information transfers mitigates the risk of information, including encrypted representations of information, produced by the actions of prior users/roles (or the actions of processes acting on behalf of prior users/roles) from being available to any current users/roles (or current processes) that obtain access to shared system resources (e.g., registers, main memory, hard disks) after those resources have been released back to information systems. The control of information in shared resources is also commonly referred to as object reuse and residual information protection. This requirement generally applies to the design of an information technology product, but it can also apply to the configuration of particular information system components that are, or use, such products. This can be verified by acceptance/validation processes in DoD or other government agencies. There may be shared resources with configurable protections (e.g., files in storage) that may be assessed on specific information system components.

ℹ️ Check
Examine the SYSTEM CONFIG file. If the "Feature" statement specifies ENABLE CLEAR_TDISK, this is not a finding.

✔️ Fix
Ensure that the following statement is in the SYSTEM CONFIG file: FEATURES ENABLE CLEAR_TDISK Further, before a minidisk is assigned to a user, the minidisk must be formatted to clear it of any residual data. CMS FORMAT, ICKDSF, or any other low-level formatting program that erases all of the data on the minidisk may be used.