=========================================================== == Subject: Samba AD users with permission to write to == an account can impersonate arbitrary services. == == CVE ID#: CVE-2022-0336 == == Versions: Samba 4.0.0 and later == == Summary: Checks in the Samba AD DC to prevent aliased == SPNs could be bypassed, giving users who can == write to an account's servicePrincipalName == attribute the ability to impersonate services. =========================================================== =========== Description =========== The Samba AD DC includes checks when adding service principals names (SPNs) to an account to ensure that SPNs do not alias with those already in the database. Some of these checks are able to be bypassed if an account modification re-adds an SPN that was previously present on that account, such as one added when a computer is joined to a domain. An attacker who has the ability to write to an account can exploit this to perform a denial-of-service attack by adding an SPN that matches an existing service. Additionally, an attacker who can intercept traffic can impersonate existing services, resulting in a loss of confidentiality and integrity. ================== Patch Availability ================== Patches addressing both these issues have been posted to: https://www.samba.org/samba/security/ Additionally, Samba 4.13.17, 4.14.12, and 4.15.4 have been issued as security releases to correct the defect. Samba administrators are advised to upgrade to these releases or apply the patch as soon as possible. ================== CVSSv3 calculation ================== CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (8.8) ========== Workaround ========== None. ======= Credits ======= Originally reported by Kees van Vloten. Analysis, patches, and this advisory by Joseph Sutton of Catalyst and the Samba Team. ========================================================== == Our Code, Our Bugs, Our Responsibility. == The Samba Team ==========================================================