Windows Server 2019 must prevent NTLM from falling back to a Null session.
An XCCDF Rule
Description
<VulnDiscussion>NTLM sessions that are allowed to fall back to Null (unauthenticated) sessions may gain unauthorized access.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-205917r569188_rule
- Severity
- Medium
- References
- Updated
Remediation - Manual Procedure
Configure the policy value for Computer Configuration >> Windows Settings >> Security Settings >> Local Policies >> Security Options >> "Network security: Allow LocalSystem NULL session fallback" to "Disabled".