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 |