Bug 2019726 (CVE-2020-25718)

Summary:	CVE-2020-25718 samba: Samba AD DC did not correctly sandbox Kerberos tickets issues by an RODC
Product:	[Other] Security Response	Reporter:	Huzaifa S. Sidhpurwala <huzaifas>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	abokovoy, anoopcs, asn, dkarpele, gdeschner, hvyas, iboukris, jarrpa, jstephen, lmohanty, madam, pfilipen, puebele, rhs-smb, sbose, security-response-team, ssorce
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	samba 4.15.2, samba 4.14.10, samba 4.13.14	Doc Type:	If docs needed, set a value
Doc Text:	A flaw was found in the way samba, as an Active Directory Domain Controller, is able to support an RODC (read-only domain controller). This would allow an RODC to print administrator tickets.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-11-10 03:21:14 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2021718
Bug Blocks:	1976705, 2022412

Description Huzaifa S. Sidhpurwala 2021-11-03 09:00:10 UTC

As per upstream advisory:


Samba as an Active Directory Domain Controller is able to support an RODC, which is meant to have minimal privileges in a domain.

However, in accepting a ticket from a Samba or Windows RODC, Samba was not confirming that the RODC is authorized to print such a ticket, via the msDS-NeverRevealGroup and msDS-RevealOnDemandGroup (typically "Allowed RODC Replication Group" and "Denied RODC Replciation Group").

This would allow an RODC to print administrator tickets.

Comment 1 Huzaifa S. Sidhpurwala 2021-11-10 02:54:09 UTC

Created samba tracking bugs for this issue:

Affects: fedora-all [bug 2021718]

Comment 2 Product Security DevOps Team 2021-11-10 03:21:12 UTC

This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2020-25718