Title

Windows Server 2019 permissions for the Windows installation directory must conform to minimum requirements. (Cat II impact)

Discussion

Changing the system's file and directory permissions allows the possibility of unauthorized and anonymous modification to the operating system and installed applications. The default permissions are adequate when the Security Option "Network access: Let Everyone permissions apply to anonymous users" is set to "Disabled" (WN19-SO-000240). Satisfies: SRG-OS-000312-GPOS-00122, SRG-OS-000312-GPOS-00123, SRG-OS-000312-GPOS-00124

Check Content

The default permissions are adequate when the Security Option "Network access: Let Everyone permissions apply to anonymous users" is set to "Disabled" (WN19-SO-000240). Review the permissions for the Windows installation directory (usually C:\Windows). Non-privileged groups such as Users or Authenticated Users must not have greater than "Read & execute" permissions. Individual accounts must not be used to assign permissions. If permissions are not as restrictive as the default permissions listed below, this is a finding: Viewing in File Explorer: For each folder, view the Properties. Select the "Security" tab and the "Advanced" button. Default permissions: \Windows Type - "Allow" for all Inherited from - "None" for all Principal - Access - Applies to TrustedInstaller - Full control - This folder and subfolders SYSTEM - Modify - This folder only SYSTEM - Full control - Subfolders and files only Administrators - Modify - This folder only Administrators - Full control - Subfolders and files only Users - Read & execute - This folder, subfolders, and files CREATOR OWNER - Full control - Subfolders and files only ALL APPLICATION PACKAGES - Read & execute - This folder, subfolders, and files ALL RESTRICTED APPLICATION PACKAGES - Read & execute - This folder, subfolders, and files Alternately, use icacls: Open a Command prompt (admin). Enter "icacls" followed by the directory: "icacls c:\windows" The following results should be displayed for each when entered: c:\windows NT SERVICE\TrustedInstaller:(F) NT SERVICE\TrustedInstaller:(CI)(IO)(F) NT AUTHORITY\SYSTEM:(M) NT AUTHORITY\SYSTEM:(OI)(CI)(IO)(F) BUILTIN\Administrators:(M) BUILTIN\Administrators:(OI)(CI)(IO)(F) BUILTIN\Users:(RX) BUILTIN\Users:(OI)(CI)(IO)(GR,GE) CREATOR OWNER:(OI)(CI)(IO)(F) APPLICATION PACKAGE AUTHORITY\ALL APPLICATION PACKAGES:(RX) APPLICATION PACKAGE AUTHORITY\ALL APPLICATION PACKAGES:(OI)(CI)(IO)(GR,GE) APPLICATION PACKAGE AUTHORITY\ALL RESTRICTED APPLICATION PACKAGES:(RX) APPLICATION PACKAGE AUTHORITY\ALL RESTRICTED APPLICATION PACKAGES:(OI)(CI)(IO)(GR,GE) Successfully processed 1 files; Failed processing 0 files

Fix Text

Maintain the default file ACLs and configure the Security Option "Network access: Let Everyone permissions apply to anonymous users" to "Disabled" (WN19-SO-000240). Default permissions: Type - "Allow" for all Inherited from - "None" for all Principal - Access - Applies to TrustedInstaller - Full control - This folder and subfolders SYSTEM - Modify - This folder only SYSTEM - Full control - Subfolders and files only Administrators - Modify - This folder only Administrators - Full control - Subfolders and files only Users - Read & execute - This folder, subfolders, and files CREATOR OWNER - Full control - Subfolders and files only ALL APPLICATION PACKAGES - Read & execute - This folder, subfolders, and files ALL RESTRICTED APPLICATION PACKAGES - Read & execute - This folder, subfolders, and files

Additional Identifiers

Rule ID: SV-205736r958702_rule

Vulnerability ID: V-205736

Group Title: SRG-OS-000312-GPOS-00122

Expert Comments

CCIs tied to check.

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