The issue is related to the PerformTicketSignature registry subkey value in CVE-2020-17049, a security feature bypass bug in Kerberos Key Distribution Center (KDC) that Microsoft fixed on November 2020 Patch Tuesday.

CVE-2020-17049, the tech company explains in an advisory, resides in the manner in which KDC determines whether tickets are eligible for delegation via Kerberos Constrained Delegation (KCD).

“To exploit the vulnerability, a compromised service that is configured to use KCD could tamper with a service ticket that is not valid for delegation to force the KDC to accept it. The update addresses this vulnerability by changing how the KDC validates service tickets used with KCD,” Microsoft notes.