Security Update for Windows Authentication Methods (3178465)
Published: August 9, 2016 | Updated: October 11, 2016
Version: 2.0
Executive Summary
This security update resolves multiple vulnerabilities in Microsoft Windows. The more severe of the vulnerabilities could allow elevation of privilege if an attacker runs a specially crafted application on a domain-joined system.
This security update is rated Important for all supported releases of Microsoft Windows. For more information, see the AffectedSoftwareand Vulnerability Severity Ratings section.
The update addresses the vulnerabilities by modifying how Windows authentication methods handle the establishment of secure channels. For more information about the vulnerabilities, see the VulnerabilityInformation section.
Affected Software and Vulnerability Severity Ratings
The following software versions or editions are affected. Versions or editions that are not listed are either past their support life cycle or are not affected. To determine the support life cycle for your software version or edition, see Microsoft Support Lifecycle.
The severity ratings indicated for each affected software assume the potential maximum impact of the vulnerability. For information regarding the likelihood, within 30 days of this security bulletin’s release, of the exploitability of the vulnerability in relation to its severity rating and security impact, please see the Exploitability Index in the August bulletin summary.
[2]Beginning with the October 2016 release, Microsoft is changing the update servicing model for Windows 7, Windows Server 2008 R2, Windows 8.1, Windows Server 2012, and Windows Server 2012 R2. For more information, please see this Microsoft TechNet article.
[3]Windows 10 updates are cumulative. The monthly security release includes all security fixes for vulnerabilities that affect Windows 10, in addition to non-security updates. The updates are available via the Microsoft Update Catalog.
*The Updates Replaced column shows only the latest update in a chain of superseded updates. For a comprehensive list of updates replaced, go to the Microsoft Update Catalog, search for the update KB number, and then view update details (updates replaced information is on the Package Details tab).
**Note **The vulnerabilities discussed in this bulletin affect Windows Server 2016 Technical Preview 5. To be protected from the vulnerabilities, Microsoft recommends that customers running this operating system apply the current update, which is available from Windows Update.
Vulnerability Information
Netlogon Elevation of Privilege Vulnerability - CVE-2016-3300
An elevation of privilege vulnerability exists when Windows Netlogon improperly establishes a secure communications channel to a domain controller. An attacker who successfully exploited the vulnerability could run a specially crafted application on a domain-joined system. To exploit the vulnerability, an attacker would require access to a domain-joined machine that points to a domain controller running either Windows Server 2012 or Windows Server 2012 R2. The update addresses the vulnerability by modifying how Netlogon handles the establishment of secure channels.
The following table contains links to the standard entry for each vulnerability in the Common Vulnerabilities and Exposures list:
A security feature bypass vulnerability exists in Windows when Kerberos improperly handles a password change request and falls back to NT LAN Manager (NTLM) Authentication Protocol as the default authentication protocol.
An attacker who successfully exploited this vulnerability could use it to bypass Kerberos authentication. To exploit this vulnerability, an attacker would have to be able to launch a man-in-the-middle (MiTM) attack against the traffic passing between a domain controller and the target machine. The update addresses this vulnerability by preventing Kerberos from falling back to NTLM as the default authentication protocol during a domain account password change.
Microsoft has not identified any mitigating factors for this vulnerability.
Workarounds
Microsoft has not identified any workarounds for this vulnerability.
Security Update Deployment
For Security Update Deployment information, see the Microsoft Knowledge Base article referenced in the Executive Summary.
Acknowledgments
Microsoft recognizes the efforts of those in the security community who help us protect customers through coordinated vulnerability disclosure. See Acknowledgments for more information.
Disclaimer
The information provided in the Microsoft Knowledge Base is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.
V1.1 (August 10, 2016): Bulletin revised to correct the security impact for CVE-2016-3237 from elevation of privilege to security feature bypass. This is an informational change only. Customers who have already successfully installed the update do not need to take any action.
V1.2 (September 2, 2016): Bulletin revised to correct the Mitigating Factors section for CVE-2016-3237 — Microsoft has not identified any mitigations for this vulnerability.
V2.0 (October 11, 2016): To address issues with Security Update 3167679, Microsoft re-released MS16-101 to address known issues with CVE-2016-3237. See Microsoft Knowledge Base Article 3167679 for more information.
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