CVE-2019-14870

samba: The DelegationNotAllowed Kerberos feature restriction was not being applied when processing protocol transition requests (S4U2Self), in the AD DC KDC

Published Dec 10, 2019 CVSS 3.1 · 5.4 Medium EPSS 2.7% KEV · Not listed
Description
All Samba versions 4.x.x before 4.9.17, 4.10.x before 4.10.11 and 4.11.x before 4.11.3 have an issue, where the S4U (MS-SFU) Kerberos delegation model includes a feature allowing for a subset of clients to be opted out of constrained delegation in any way, either S4U2Self or regular Kerberos authentication, by forcing all tickets for these clients to be non-forwardable. In AD this is implemented by a user attribute delegation_not_allowed (aka not-delegated), which translates to disallow-forwardable. However the Samba AD DC does not do that for S4U2Self and does set the forwardable flag even if the impersonated client has the not-delegated flag set.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-2668-1 samba security update
Debian DLA Debian DLA DLA-3206-1 heimdal security update
EUVD EUVD EUVD-2019-5985 All Samba versions 4.x.x before 4.9.17, 4.10.x before 4.10.11 and 4.11.x before 4.11.3 have an issue, where the S4U (MS-SFU) Kerberos delegation model includes a feature allowing for a subset of clients to be opted out of constrained delegation in any way, either S4U2Self or regular Kerberos authentication, by forcing all tickets for these clients to be non-forwardable. In AD this is implemented by a user attribute delegation_not_allowed (aka not-delegated), which translates to disallow-forwardable. However the Samba AD DC does not do that for S4U2Self and does set the forwardable flag even if the impersonated client has the not-delegated flag set.
Ubuntu USN Ubuntu USN USN-4217-1 Samba vulnerabilities
Ubuntu USN Ubuntu USN USN-4217-2 Samba vulnerabilities
History

No history.

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Aug 5, 2024, 12:26 AM
Reserved
Aug 10, 2019, 12:00 AM
Status
Modified
Published
Dec 10, 2019, 11:15 PM
Modified
Jun 17, 2026, 2:19 AM
Severity
Moderate
Public date
Dec 10, 2019, 12:00 AM