Note: This is a public test instance of Red Hat Bugzilla. The data contained within is a snapshot of the live data so any changes you make will not be reflected in the production Bugzilla. Email is disabled so feel free to test any aspect of the site that you want. File any problems you find or give feedback at bugzilla.redhat.com.

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: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED NOTABUG QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: 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: 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