Attacker Value
Unknown
(2 users assessed)
Exploitability
Unknown
(2 users assessed)
User Interaction
None
Privileges Required
High
Attack Vector
Network
4

CVE-2020-17049

Disclosure Date: November 11, 2020 •
CVE-2020-17049 CVSS v3 Base Score: 6.6
Exploited in the Wild
Reported by jakekarnes42
View Source Details
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

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.

Add Assessment

2
Technical Analysis

Based on https://twitter.com/jakekarnes42/status/1329825159247642624
“The vulnerability impacts constrained delegation, which could be present in a single domain/forest. “
Note that the patch itself requires registry keys to be entered. Merely installing updates does not appear to protect the domain. There are issues introduced by this patch with Citrix and Federated Authentication service. (source https://twitter.com/mrgrayaz/status/1328517824633978912)

Log in to Add Reply
CVSS V3 Severity and Metrics
Base Score:
6.6 Medium
Impact Score:
5.9
Exploitability Score:
0.7
Vector:
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
Attack Vector (AV):
Network
Attack Complexity (AC):
High
Privileges Required (PR):
High
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
High
Integrity (I):
High
Availability (A):
High

General Information

Offensive Application
Unknown
Utility Class
Unknown
Ports
Unknown
OS
Unknown
Vulnerable Versions
Windows Server 2019 10.0.17763.2061
Windows Server 2019 (Server Core installation) 10.0.17763.2061
Windows Server, version 1909 (Server Core installation) publication
Windows Server, version 1903 (Server Core installation) publication
Windows Server version 2004 10.0.19041.1110
Windows Server 2016 10.0.14393.4530
Windows Server 2016 (Server Core installation) 10.0.14393.4530
Windows Server 2008 Service Pack 2 6.0.6003.21167
Windows Server 2008 Service Pack 2 (Server Core installation) 6.0.6003.21167
Windows Server 2008 Service Pack 2 6.0.6003.21167
Windows Server 2008 R2 Service Pack 1 6.1.7601.25661
Windows Server 2008 R2 Service Pack 1 (Server Core installation) 6.1.7601.25661
Windows Server 2012 6.2.9200.23409
Windows Server 2012 (Server Core installation) 6.2.9200.23409
Windows Server 2012 R2 6.3.9600.20069
Windows Server 2012 R2 (Server Core installation) 6.3.9600.20069
Windows Server version 20H2 10.0.19041.1110
Prerequisites
Unknown
Discovered By
Unknown
PoC Author
Unknown
Metasploit Module
Unknown
Reporter
Unknown

Vendors

  • microsoft,
  • samba

Products

  • samba,
  • windows server 2012,
  • windows server 2012 r2,
  • windows server 2016 -,
  • windows server 2016 1903,
  • windows server 2016 1909,
  • windows server 2016 2004,
  • windows server 2016 20h2,
  • windows server 2019 -

Exploited in the Wild

Reported by:
Technical Analysis