Title

Windows Server 2019 default permissions for the HKEY_LOCAL_MACHINE registry hive must be maintained. (Cat II impact)

Discussion

The registry is integral to the function, security, and stability of the Windows system. Changing the system's registry permissions allows the possibility of unauthorized and anonymous modification to the operating system.

Check Content

Review the registry permissions for the keys of the HKEY_LOCAL_MACHINE hive noted below. If any non-privileged groups such as Everyone, Users, or Authenticated Users have greater than Read permission, this is a finding. If permissions are not as restrictive as the default permissions listed below, this is a finding: Run "Regedit". Right-click on the registry areas noted below. Select "Permissions" and the "Advanced" button. HKEY_LOCAL_MACHINE\SECURITY Type - "Allow" for all Inherited from - "None" for all Principal - Access - Applies to SYSTEM - Full Control - This key and subkeys Administrators - Special - This key and subkeys HKEY_LOCAL_MACHINE\SOFTWARE Type - "Allow" for all Inherited from - "None" for all Principal - Access - Applies to Users - Read - This key and subkeys Administrators - Full Control - This key and subkeys SYSTEM - Full Control - This key and subkeys CREATOR OWNER - Full Control - This key and subkeys ALL APPLICATION PACKAGES - Read - This key and subkeys HKEY_LOCAL_MACHINE\SYSTEM Type - "Allow" for all Inherited from - "None" for all Principal - Access - Applies to Users - Read - This key and subkeys Administrators - Full Control - This key and subkeys SYSTEM - Full Control - This key and subkeys CREATOR OWNER - Full Control - Subkeys only ALL APPLICATION PACKAGES - Read - This key and subkeys Server Operators – Read – This Key and subkeys (Domain controllers only) Other examples under the noted keys may also be sampled. There may be some instances where non-privileged groups have greater than Read permission. Microsoft has given Read permission to the SOFTWARE and SYSTEM registry keys in Windows Server 2019 to the following SID, this is currently not a finding. S-1-15-3-1024-1065365936-1281604716-3511738428-1654721687-432734479-3232135806-4053264122-3456934681 If the defaults have not been changed, these are not a finding.

Fix Text

Maintain the default permissions for the HKEY_LOCAL_MACHINE registry hive. The default permissions of the higher-level keys are noted below. HKEY_LOCAL_MACHINE\SECURITY Type - "Allow" for all Inherited from - "None" for all Principal - Access - Applies to SYSTEM - Full Control - This key and subkeys Administrators - Special - This key and subkeys HKEY_LOCAL_MACHINE\SOFTWARE Type - "Allow" for all Inherited from - "None" for all Principal - Access - Applies to Users - Read - This key and subkeys Administrators - Full Control - This key and subkeys SYSTEM - Full Control - This key and subkeys CREATOR OWNER - Full Control - This key and subkeys ALL APPLICATION PACKAGES - Read - This key and subkeys HKEY_LOCAL_MACHINE\SYSTEM Type - "Allow" for all Inherited from - "None" for all Principal - Access - Applies to Users - Read - This key and subkeys Administrators - Full Control - This key and subkeys SYSTEM - Full Control - This key and subkeys CREATOR OWNER - Full Control - Subkeys only ALL APPLICATION PACKAGES - Read - This key and subkeys Server Operators – Read – This Key and subkeys (Domain controllers only) Microsoft has also given Read permission to the SOFTWARE and SYSTEM registry keys in Windows Server 2019 to the following SID. S-1-15-3-1024-1065365936-1281604716-3511738428-1654721687-432734479-3232135806-4053264122-3456934681

Additional Identifiers

Rule ID: SV-205737r877392_rule

Vulnerability ID: V-205737

Group Title: SRG-OS-000324-GPOS-00125

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.