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.
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Samba | Samba | 4.0.0 (including) | 4.9.17 (excluding) |
| Samba | Samba | 4.10.0 (including) | 4.10.11 (excluding) |
| Samba | Samba | 4.11.0 (including) | 4.11.3 (excluding) |
| Samba | Ubuntu | bionic | * |
| Samba | Ubuntu | devel | * |
| Samba | Ubuntu | disco | * |
| Samba | Ubuntu | eoan | * |
| Samba | Ubuntu | trusty | * |
| Samba | Ubuntu | trusty/esm | * |
| Samba | Ubuntu | upstream | * |
| Samba | Ubuntu | xenial | * |