CVE-2022-37966: Windows Kerberos RC4-HMAC Elevation of Privilege Vulnerability

Overview

Severity
High (CVSS 8.1)
CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Category
Elevation of Privilege
Exploit Status
Not Exploited
Exploitation Likelihood
More Likely
Patch Tuesday
2022-Nov
Released
2022-11-08
Last Updated
2022-11-17
EPSS Score
1.38% (percentile: 80.3%)

FAQ

How could an attacker exploit this vulnerability? An unauthenticated attacker could conduct an attack that could leverage cryptographic protocol vulnerabilities in RFC 4757 (Kerberos encryption type RC4-HMAC-MD5) and MS-PAC (Privilege Attribute Certificate Data Structure specification) to bypass security features in a Windows AD environment. Where can I find more information about these changes? For more information please see How to manage the Kerberos Protocol changes related to CVE-2022-37966. I am running Windows Server 2022 Datacenter: Azure Edition (Server Core) but the hotpatch (Windows Server 2022 Datacenter: Azure Edition (Hotpatch)) for it is not listed in the Security Updates table. Is there an update that I can apply for this edition of Windows Server 2022? The update to address this vulnerability for Windows Server 2022 Datacenter: Azure Edition (Server Core) is not hotpatchable and is therefore not included in the November Hotpatch KB (5019080). Customers running Windows Server 2022 Datacenter: Azure Edition (Server Core) as a domain controller should install the update for Windows Server 2022 (5019081). This update will require a computer restart. What privileges could be gained by an attacker who successfully exploited the vulnerability? An attacker who successfully exploited this vulnerability could gain administrator privileges. According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability? Successful exploitation of this vulnerability requires an attacker to gather information specific to the environment of the targeted component. There is a known issue documented in the security updates that address this vulnerability, where Kerberos authentication might fail for user, computer, service, and GMSA accounts when serviced by Windows domain controllers that have installed Windows security updates released on November 8, 2022. Has an update been released that addresses this known issue? Yes. The issue i

Detection & Weaponization (1 sources)

Maturity: Detection

  • Sigma rules: Potential KDC RC4-HMAC Downgrade Exploit - CVE-2022-37966

Affected Products (16)

Windows

  • Windows Server 2019
  • Windows Server 2019 (Server Core installation)
  • Windows Server 2022
  • Windows Server 2022 (Server Core installation)
  • Windows Server 2016
  • Windows Server 2016 (Server Core installation)

ESU

  • Windows Server 2008 for 32-bit Systems Service Pack 2
  • Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)
  • Windows Server 2008 for x64-based Systems Service Pack 2
  • Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)
  • Windows Server 2008 R2 for x64-based Systems Service Pack 1
  • Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
  • Windows Server 2012
  • Windows Server 2012 (Server Core installation)
  • Windows Server 2012 R2
  • Windows Server 2012 R2 (Server Core installation)

Revision History

  • 2022-11-08: Information published.
  • 2022-11-17: To address a known issue where Kerberos authentication might fail for user, computer, service, and GMSA accounts when serviced by Windows domain controllers that have installed Windows security updates released on November 8, 2022, Microsoft is announcing the availability of out-of-band Windows updates available on the Microsoft Update Catalog. For more information see the FAQs section of this CVE and the Known Issues section of How to manage the Kerberos Protocol changes related to CVE-2022-37966.