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medium5.4

CVE-2019-14870

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…

Impact

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.

Affected products

VendorProductAffected versions
SambaSamba
from 4.0.0 before 4.9.17
from 4.10.0 before 4.10.11
from 4.11.0 before 4.11.3
FedoraprojectFedora
Versions 30, 31
CanonicalUbuntu Linux
Versions 14.04, 16.04, 18.04, 19.04, 19.10
DebianDebian Linux
Versions 9.0, 10.0
OpensuseLeap
Version 15.1

Weakness classification

CWE-285CWE-287

References