SQL Server must allow only the ISSM (or individuals or roles appointed by the ISSM) to select which auditable events are to be audited.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-79135	SQL6-D0-004400	SV-93841r1_rule		Medium

Description
Without the capability to restrict which roles and individuals can select which events are audited, unauthorized personnel may be able to prevent or interfere with the auditing of critical events. Suppression of auditing could permit an adversary to evade detection. Misconfigured audits can degrade the system's performance by overwhelming the audit log. Misconfigured audits may also make it more difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one.

Description

Without the capability to restrict which roles and individuals can select which events are audited, unauthorized personnel may be able to prevent or interfere with the auditing of critical events. Suppression of auditing could permit an adversary to evade detection. Misconfigured audits can degrade the system's performance by overwhelming the audit log. Misconfigured audits may also make it more difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one.

STIG	Date
MS SQL Server 2016 Instance Security Technical Implementation Guide	2018-03-09

Details

Check Text ( C-78727r1_chk )
Obtain the list of approved audit maintainers from the system documentation. Review the server roles and individual logins that have the following role memberships, all of which enable the ability to create and maintain audit definitions. sysadmin dbcreator Review the server roles and individual logins that have the following permissions, all of which enable the ability to create and maintain audit definitions. ALTER ANY SERVER AUDIT CONTROL SERVER ALTER ANY DATABASE CREATE ANY DATABASE Use the following query to determine the roles and logins that have the listed permissions: SELECT-- DISTINCT CASE WHEN SP.class_desc IS NOT NULL THEN CASE WHEN SP.class_desc = 'SERVER' AND S.is_linked = 0 THEN 'SERVER' WHEN SP.class_desc = 'SERVER' AND S.is_linked = 1 THEN 'SERVER (linked)' ELSE SP.class_desc END WHEN E.name IS NOT NULL THEN 'ENDPOINT' WHEN S.name IS NOT NULL AND S.is_linked = 0 THEN 'SERVER' WHEN S.name IS NOT NULL AND S.is_linked = 1 THEN 'SERVER (linked)' WHEN P.name IS NOT NULL THEN 'SERVER_PRINCIPAL' ELSE '???' END AS [Securable Class], CASE WHEN E.name IS NOT NULL THEN E.name WHEN S.name IS NOT NULL THEN S.name WHEN P.name IS NOT NULL THEN P.name ELSE '???' END AS [Securable], P1.name AS [Grantee], P1.type_desc AS [Grantee Type], sp.permission_name AS [Permission], sp.state_desc AS [State], P2.name AS [Grantor], P2.type_desc AS [Grantor Type], R.name AS [Role Name] FROM sys.server_permissions SP INNER JOIN sys.server_principals P1 ON P1.principal_id = SP.grantee_principal_id INNER JOIN sys.server_principals P2 ON P2.principal_id = SP.grantor_principal_id FULL OUTER JOIN sys.servers S ON SP.class_desc = 'SERVER' AND S.server_id = SP.major_id FULL OUTER JOIN sys.endpoints E ON SP.class_desc = 'ENDPOINT' AND E.endpoint_id = SP.major_id FULL OUTER JOIN sys.server_principals P ON SP.class_desc = 'SERVER_PRINCIPAL' AND P.principal_id = SP.major_id FULL OUTER JOIN sys.server_role_members SRM ON P.principal_id = SRM.member_principal_id LEFT OUTER JOIN sys.server_principals R ON SRM.role_principal_id = R.principal_id WHERE sp.permission_name IN ('ALTER ANY SERVER AUDIT','CONTROL SERVER','ALTER ANY DATABASE','CREATE ANY DATABASE') OR R.name IN ('sysadmin','dbcreator') If any of the logins, roles, or role memberships returned have permissions that are not documented, or the documented audit maintainers do not have permissions, this is a finding.

Check Text ( C-78727r1_chk )

Obtain the list of approved audit maintainers from the system documentation.

Review the server roles and individual logins that have the following role memberships, all of which enable the ability to create and maintain audit definitions.

sysadmin
dbcreator

Review the server roles and individual logins that have the following permissions, all of which enable the ability to create and maintain audit definitions.

ALTER ANY SERVER AUDIT
CONTROL SERVER
ALTER ANY DATABASE
CREATE ANY DATABASE

Use the following query to determine the roles and logins that have the listed permissions:

SELECT-- DISTINCT
CASE
WHEN SP.class_desc IS NOT NULL THEN
CASE
WHEN SP.class_desc = 'SERVER' AND S.is_linked = 0 THEN 'SERVER'
WHEN SP.class_desc = 'SERVER' AND S.is_linked = 1 THEN 'SERVER (linked)'
ELSE SP.class_desc
END
WHEN E.name IS NOT NULL THEN 'ENDPOINT'
WHEN S.name IS NOT NULL AND S.is_linked = 0 THEN 'SERVER'
WHEN S.name IS NOT NULL AND S.is_linked = 1 THEN 'SERVER (linked)'
WHEN P.name IS NOT NULL THEN 'SERVER_PRINCIPAL'
ELSE '???'
END AS [Securable Class],
CASE
WHEN E.name IS NOT NULL THEN E.name
WHEN S.name IS NOT NULL THEN S.name
WHEN P.name IS NOT NULL THEN P.name
ELSE '???'
END AS [Securable],
P1.name AS [Grantee],
P1.type_desc AS [Grantee Type],
sp.permission_name AS [Permission],
sp.state_desc AS [State],
P2.name AS [Grantor],
P2.type_desc AS [Grantor Type],
R.name AS [Role Name]
FROM
sys.server_permissions SP
INNER JOIN sys.server_principals P1
ON P1.principal_id = SP.grantee_principal_id
INNER JOIN sys.server_principals P2
ON P2.principal_id = SP.grantor_principal_id

FULL OUTER JOIN sys.servers S
ON SP.class_desc = 'SERVER'
AND S.server_id = SP.major_id

FULL OUTER JOIN sys.endpoints E
ON SP.class_desc = 'ENDPOINT'
AND E.endpoint_id = SP.major_id

FULL OUTER JOIN sys.server_principals P
ON SP.class_desc = 'SERVER_PRINCIPAL'
AND P.principal_id = SP.major_id

FULL OUTER JOIN sys.server_role_members SRM
ON P.principal_id = SRM.member_principal_id

LEFT OUTER JOIN sys.server_principals R
ON SRM.role_principal_id = R.principal_id
WHERE sp.permission_name IN ('ALTER ANY SERVER AUDIT','CONTROL SERVER','ALTER ANY DATABASE','CREATE ANY DATABASE')
OR R.name IN ('sysadmin','dbcreator')

If any of the logins, roles, or role memberships returned have permissions that are not documented, or the documented audit maintainers do not have permissions, this is a finding.

Fix Text (F-85887r1_fix)
Create a server role specifically for audit maintainers and give it permission to maintain audits without granting it unnecessary permissions (the role name used here is an example; other names may be used): CREATE SERVER ROLE SERVER_AUDIT_MAINTAINERS; GO GRANT ALTER ANY SERVER AUDIT TO SERVER_AUDIT_MAINTAINERS; GO Use REVOKE and/or DENY and/or ALTER SERVER ROLE ... DROP MEMBER ... statements to remove the ALTER ANY SERVER AUDIT permission from all logins. Then, for each authorized login, run the statement: ALTER SERVER ROLE SERVER_AUDIT_MAINTAINERS ADD MEMBER; GO Use REVOKE and/or DENY and/or ALTER SERVER ROLE ... DROP MEMBER ... statements to remove CONTROL SERVER, ALTER ANY DATABASE and CREATE ANY DATABASE permissions from logins that do not need them.

Fix Text (F-85887r1_fix)

Create a server role specifically for audit maintainers and give it permission to maintain audits without granting it unnecessary permissions (the role name used here is an example; other names may be used):

CREATE SERVER ROLE SERVER_AUDIT_MAINTAINERS;
GO

GRANT ALTER ANY SERVER AUDIT TO SERVER_AUDIT_MAINTAINERS;
GO

Use REVOKE and/or DENY and/or ALTER SERVER ROLE ... DROP MEMBER ... statements to remove the ALTER ANY SERVER AUDIT permission from all logins. Then, for each authorized login, run the statement:

ALTER SERVER ROLE SERVER_AUDIT_MAINTAINERS ADD MEMBER;
GO

Use REVOKE and/or DENY and/or ALTER SERVER ROLE ... DROP MEMBER ... statements to remove CONTROL SERVER, ALTER ANY DATABASE and CREATE ANY DATABASE permissions from logins that do not need them.