CVE-2020-17049

Description

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.

CVSS Metrics

• v3.1•MEDIUM•Score: 6.6CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
• v3.1•MEDIUM•Score: 6.6CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
• v2.0•HIGH•Score: 9AV:N/AC:L/Au:S/C:C/I:C/A:C

EPSS Trends

Current EPSS score: 25.55%• Percentile: 96%

Techniques & Countermeasures

• CWE-863•Incorrect Authorization

  The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

Affected Systems

• microsoft•windows server 2008 service pack 2

  ≥ 6.0.0, < 6.0.6003.21167

• microsoft•windows server 2008 r2 service pack 1

  ≥ 6.1.0, < 6.1.7601.25661

• microsoft•windows server 2008 r2 service pack 1 (server core installation)

  ≥ 6.0.0, < 6.1.7601.25661

• microsoft•windows server 2008 service pack 2

  ≥ 6.0.0, < 6.0.6003.21167

• microsoft•windows server 2008 service pack 2 (server core installation)

  ≥ 6.0.0, < 6.0.6003.21167

• microsoft•windows server 2012

  r2 | ≥ 6.2.0, < 6.2.9200.23409

• microsoft•windows server 2012 r2

  ≥ 6.3.0, < 6.3.9600.20069

• microsoft•windows server 2012 r2 (server core installation)

  ≥ 6.3.0, < 6.3.9600.20069

• microsoft•windows server 2012 (server core installation)

  ≥ 6.2.0, < 6.2.9200.23409

• microsoft•windows server 2016

  na | 20h2 | 1903 | 1909 | 2004 | ≥ 10.0.0, < 10.0.14393.4530

• microsoft•windows server 2016 (server core installation)

  ≥ 10.0.0, < 10.0.14393.4530

• microsoft•windows server 2019

  na | ≥ 10.0.0, < 10.0.17763.2061

• microsoft•windows server 2019 (server core installation)

  ≥ 10.0.0, < 10.0.17763.2061

• microsoft•windows server, version 1903 (server core installation)

  ≥ 10.0.0, < publication

• microsoft•windows server, version 1909 (server core installation)

  ≥ 10.0.0, < publication

• microsoft•windows server version 2004

  ≥ 10.0.0, < 10.0.19041.1110

• microsoft•windows server version 20h2

  ≥ 10.0.0, < 10.0.19041.1110

• samba•samba

  ≥ 4.1.0, < 4.13.13 | ≥ 4.14.0, < 4.14.9 | ≥ 4.15.0, < 4.15.1

References (3)

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-17049
• http://www.openwall.com/lists/oss-security/2021/11/10/3
• https://security.gentoo.org/glsa/202309-06