CVE-2019-14870 Information

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.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

Reference

http://lists.opensuse.org/opensuse-security-announce/2019-12/msg00038.html https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-14870 https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PJH3ROOFYMOATD2UEPC47P5RPBDTY77E/ https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/WNKA4YIPV7AZR7KK3GW6L3HKGHSGJZFE/ https://security.gentoo.org/glsa/202003-52 https://security.netapp.com/advisory/ntap-20191210-0002/ https://usn.ubuntu.com/4217-1/ https://usn.ubuntu.com/4217-2/ https://www.samba.org/samba/security/CVE-2019-14870.html https://www.synology.com/security/advisory/Synology_SA_19_40

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

LOW

Availability Impact

LOW

Base Score

NONE

Base Severity

5.4