Описание
Kerberos KDC Security Feature Bypass Vulnerability
A security feature bypass vulnerability exists in the way Key Distribution Center (KDC) determines if a service ticket can be used 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.
FAQ
Do I need to take further steps to be protected from this vulnerability?
Yes. As of April 13, 2021, customers who have already installed the November 10, 2020 security updates need to do the following:
- This update assumes that all Domain Controllers are updated with the December 8, 2020 updates or later updates. The December 8, 2020 security updates include fixes for all known issues originally introduced by the November 10, 2020 release of CVE-2020-17049. This update also adds support for Windows Server 2008 SP2 and Windows Server 2008 R2.
- Install the updates released on April 13, 2021. These updates remove the PerformTicketSignature setting 0. Setting PerformTicketSignature to 0 after this update is installed will have the same effect as setting PerformTicketSignature to 1. The Domain Controllers (DC)s will be in Deployment mode.
For more information and further steps to enable full protection on domain controller servers see Managing deployment of Kerberos S4U changes for CVE-2020-17049.
Обновления
| Продукт | Статья | Обновление |
|---|---|---|
| Windows Server 2008 for 32-bit Systems Service Pack 2 | ||
| 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 (Server Core installation) | ||
| Windows Server 2008 R2 for x64-based Systems Service Pack 1 | ||
| Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation) | ||
| Windows Server 2012 | ||
| Windows Server 2012 (Server Core installation) | ||
| Windows Server 2012 R2 | ||
| Windows Server 2012 R2 (Server Core installation) |
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Возможность эксплуатации
Publicly Disclosed
Exploited
Latest Software Release
Older Software Release
DOS
EPSS
6.6 Medium
CVSS3
Связанные уязвимости
A security feature bypass vulnerability exists in the way Key Distribution Center (KDC) determines if a service ticket can be used 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.
A security feature bypass vulnerability exists in the way Key Distribution Center (KDC) determines if a service ticket can be used 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.
ELSA-2023-2570: krb5 security, bug fix, and enhancement update (MODERATE)
Уязвимость компонента Kerberos KDC операционных систем Windows, позволяющая нарушителю обойти существующие ограничения безопасности и получить несанкционированный доступ к приложению
EPSS
6.6 Medium
CVSS3