Microsoft releases out-of-band update to fix Kerberos auth issues caused by a patch for CVE-2022-37966

Microsoft released an out-of-band update to fix problems tied to a recent Windows security patch that caused Kerberos authentication issues.

Microsoft released an out-of-band update to address issues caused by a recent Windows security patch that causes Kerberos authentication problems.

Microsoft Patch Tuesday security updates for November 2022 addressed a privilege escalation vulnerability, tracked as CVE-2022-37966, that impacts Windows Server.

An attacker can trigger this flaw to gain administrator privileges on vulnerable systems.

“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.” reads the advisory published by Microsoft.

After the release of the Patch Tuesday security updates, users started reporting issues related to the Kerberos authentication.

The IT giant investigated the reports and developed an out-of-band update to fix the problems.

“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?” continues the advisory.

“Yes. The issue is addressed by out-of-band updates released to Microsoft Update Catalog on and after November 17, 2022. Customers who have not already installed the security updates released on November 8, 2022 should install the out-of-band updates instead. Customers who have already installed the November 8, 2022 Windows security updates and who are experiencing issues should install the out-of-band updates.”

The IT giant recommends customers who have yet to install the security updates released on November 8, 2022 of only install the out-of-band updates. Customers who have already installed the Patch Tuesday security updates and are experiencing issues should install the out-of-band updates.

Microsoft is not aware of attacks in the wild exploiting the CVE-2022-37966 flaw.

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Pierluigi Paganini

(SecurityAffairs – hacking, Microsoft)

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