CVE-2019-14870

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.

How to fix CVE-2019-14870

To remediate CVE-2019-14870, upgrade the affected package to a fixed version below.

• —upgrade to 7.7.1-r0 or later
• —upgrade to 4.10.11-r0 or later
• —upgrade to 7.7.0+dfsg-1 or later
• —upgrade to 7.5.0+dfsg-3+deb10u1 or later
• —upgrade to 2:4.11.3+dfsg-1 or later

Is CVE-2019-14870 being exploited?

Low — EPSS is 4.7%, meaning exploitation activity has not been observed at scale.

Affected packages (5)

• from 0, < 7.7.1-r0
• from 0, < 4.10.11-r0
• from 0, < 7.7.0+dfsg-1
• from 0, < 7.5.0+dfsg-3+deb10u1
• from 0, < 2:4.11.3+dfsg-1

CVSS scores

References (2)

• ADVISORYsecurity.alpinelinux.org/vuln/CVE-2019-14870
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2019-14870