The Active Directory SYSVOL directory must have the proper access control permissions.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-73371	WN16-DC-000080	SV-88023r1_rule		High

Description
Improper access permissions for directory data files could allow unauthorized users to read, modify, or delete directory data. The SYSVOL directory contains public files (to the domain) such as policies and logon scripts. Data in shared subdirectories are replicated to all domain controllers in a domain.

STIG	Date
Windows Server 2016 Security Technical Implementation Guide	2019-12-12

Details

Check Text ( C-73445r1_chk )
This applies to domain controllers. It is NA for other systems. Open a command prompt. Run "net share". Make note of the directory location of the SYSVOL share. By default, this will be \Windows\SYSVOL\sysvol. For this requirement, permissions will be verified at the first SYSVOL directory level. If any standard user accounts or groups have greater than "Read & execute" permissions, this is a finding. The default permissions noted below meet this requirement. Open "Command Prompt". Run "icacls c:\Windows\SYSVOL". The following results should be displayed: NT AUTHORITY\Authenticated Users:(RX) NT AUTHORITY\Authenticated Users:(OI)(CI)(IO)(GR,GE) BUILTIN\Server Operators:(RX) BUILTIN\Server Operators:(OI)(CI)(IO)(GR,GE) BUILTIN\Administrators:(M,WDAC,WO) BUILTIN\Administrators:(OI)(CI)(IO)(F) NT AUTHORITY\SYSTEM:(F) NT AUTHORITY\SYSTEM:(OI)(CI)(IO)(F) BUILTIN\Administrators:(M,WDAC,WO) CREATOR OWNER:(OI)(CI)(IO)(F) (RX) - Read & execute Run "icacls /help" to view definitions of other permission codes. Alternately, open "File Explorer". Navigate to \Windows\SYSVOL (or the directory noted previously if different). Right-click the directory and select properties. Select the "Security" tab and click "Advanced". Default permissions: C:\Windows\SYSVOL Type - "Allow" for all Inherited from - "None" for all Principal - Access - Applies to Authenticated Users - Read & execute - This folder, subfolder, and files Server Operators - Read & execute- This folder, subfolder, and files Administrators - Special - This folder only (Special = Basic Permissions: all selected except Full control) CREATOR OWNER - Full control - Subfolders and files only Administrators - Full control - Subfolders and files only SYSTEM - Full control - This folder, subfolders, and files

Check Text ( C-73445r1_chk )

This applies to domain controllers. It is NA for other systems.

Open a command prompt.

Run "net share".

Make note of the directory location of the SYSVOL share.

By default, this will be \Windows\SYSVOL\sysvol. For this requirement, permissions will be verified at the first SYSVOL directory level.

If any standard user accounts or groups have greater than "Read & execute" permissions, this is a finding.

The default permissions noted below meet this requirement.

Open "Command Prompt".

Run "icacls c:\Windows\SYSVOL".

The following results should be displayed:

NT AUTHORITY\Authenticated Users:(RX)
NT AUTHORITY\Authenticated Users:(OI)(CI)(IO)(GR,GE)
BUILTIN\Server Operators:(RX)
BUILTIN\Server Operators:(OI)(CI)(IO)(GR,GE)
BUILTIN\Administrators:(M,WDAC,WO)
BUILTIN\Administrators:(OI)(CI)(IO)(F)
NT AUTHORITY\SYSTEM:(F)
NT AUTHORITY\SYSTEM:(OI)(CI)(IO)(F)
BUILTIN\Administrators:(M,WDAC,WO)
CREATOR OWNER:(OI)(CI)(IO)(F)

(RX) - Read & execute

Run "icacls /help" to view definitions of other permission codes.

Alternately, open "File Explorer".

Navigate to \Windows\SYSVOL (or the directory noted previously if different).

Right-click the directory and select properties.

Select the "Security" tab and click "Advanced".

Default permissions:

C:\Windows\SYSVOL
Type - "Allow" for all
Inherited from - "None" for all

Principal - Access - Applies to

Authenticated Users - Read & execute - This folder, subfolder, and files
Server Operators - Read & execute- This folder, subfolder, and files
Administrators - Special - This folder only (Special = Basic Permissions: all selected except Full control)
CREATOR OWNER - Full control - Subfolders and files only
Administrators - Full control - Subfolders and files only
SYSTEM - Full control - This folder, subfolders, and files

Fix Text (F-79813r1_fix)
Maintain the permissions on the SYSVOL directory. Do not allow greater than "Read & execute" permissions for standard user accounts or groups. The defaults below meet this requirement. C:\Windows\SYSVOL Type - "Allow" for all Inherited from - "None" for all Principal - Access - Applies to Authenticated Users - Read & execute - This folder, subfolder, and files Server Operators - Read & execute- This folder, subfolder, and files Administrators - Special - This folder only (Special = Basic Permissions: all selected except Full control) CREATOR OWNER - Full control - Subfolders and files only Administrators - Full control - Subfolders and files only SYSTEM - Full control - This folder, subfolders, and files

Fix Text (F-79813r1_fix)

Maintain the permissions on the SYSVOL directory. Do not allow greater than "Read & execute" permissions for standard user accounts or groups. The defaults below meet this requirement.

C:\Windows\SYSVOL
Type - "Allow" for all
Inherited from - "None" for all

Principal - Access - Applies to

Authenticated Users - Read & execute - This folder, subfolder, and files
Server Operators - Read & execute- This folder, subfolder, and files
Administrators - Special - This folder only (Special = Basic Permissions: all selected except Full control)
CREATOR OWNER - Full control - Subfolders and files only
Administrators - Full control - Subfolders and files only
SYSTEM - Full control - This folder, subfolders, and files