CVE-2019-14870
Published: 10 December 2019
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.
Priority
Status
Package | Release | Status |
---|---|---|
samba Launchpad, Ubuntu, Debian |
bionic |
Released
(2:4.7.6+dfsg~ubuntu-0ubuntu2.14)
|
disco |
Released
(2:4.10.0+dfsg-0ubuntu2.7)
|
|
eoan |
Released
(2:4.10.7+dfsg-0ubuntu2.3)
|
|
trusty |
Released
(2:4.3.11+dfsg-0ubuntu0.14.04.20+esm4)
Available with Ubuntu Pro or Ubuntu Pro (Infra-only) |
|
upstream |
Released
(4.11.3,4.10.11,4.9.17)
|
|
xenial |
Released
(2:4.3.11+dfsg-0ubuntu0.16.04.24)
|
Severity score breakdown
Parameter | Value |
---|---|
Base score | 5.4 |
Attack vector | Network |
Attack complexity | Low |
Privileges required | Low |
User interaction | None |
Scope | Unchanged |
Confidentiality | Low |
Integrity impact | Low |
Availability impact | None |
Vector | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N |