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.
problem types: CWE-285
affected:
{
vendor: Red Hat
product: samba
versions:
version: all versions 4.11.x before 4.11.3, status: affected
version: all versions 4.10.x before 4.10.11, status: affected
version: all versions 4.x.x before 4.9.17, status: affected
}
metrics:
cvssV3_0: [
version: 3.0
vectorString: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
attackVector: NETWORK
attackComplexity: LOW
privilegesRequired: LOW
userInteraction: NONE
scope: UNCHANGED
confidentialityImpact: LOW
integrityImpact: LOW
availabilityImpact: NONE
baseScore: 5.4
baseSeverity: MEDIUM
]