6.8 - RHSA-2016:1486

Problem Description:

An update for samba is now available for Red Hat Enterprise Linux 7.

Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Client (v. 7) - noarch, x86_64 Red Hat Enterprise Linux Client Optional (v. 7) - noarch, x86_64 Red Hat Enterprise Linux ComputeNode (v. 7) - noarch, x86_64 Red Hat Enterprise Linux ComputeNode Optional (v. 7) - noarch, x86_64 Red Hat Enterprise Linux Server (v. 7) - noarch, ppc64, ppc64le, s390x, x86_64 Red Hat Enterprise Linux Server Optional (v. 7) - noarch, ppc64, ppc64le, s390x, x86_64 Red Hat Enterprise Linux Server Resilient Storage (v. 7) - x86_64 Red Hat Enterprise Linux Workstation (v. 7) - noarch, x86_64 Red Hat Enterprise Linux Workstation Optional (v. 7) - noarch, x86_64

3. Description:

Samba is an open-source implementation of the Server Message Block (SMB) protocol and the related Common Internet File System (CIFS) protocol, which allow PC-compatible machines to share files, printers, and various information.

Security Fix(es):

* A flaw was found in the way Samba initiated signed DCE/RPC connections. A man-in-the-middle attacker could use this flaw to downgrade the connection to not use signing and therefore impersonate the server. (CVE-2016-2119)

Red Hat would like to thank the Samba project for reporting this issue. Upstream acknowledges Stefan Metzmacher as the original reporter.

Bug Fix(es):

* Previously, the "net" command in some cases failed to join the client to Active Directory (AD) because the permissions setting prevented modification of the supported Kerberos encryption type LDAP attribute. With this update, Samba has been fixed to allow joining an AD domain as a user. In addition, Samba now uses the machine account credentials to set up the Kerberos encryption types within AD for the joined machine. As a result, using "net" to join a domain now works more reliably. (BZ#1351260)

* Previously, the idmap_hash module worked incorrectly when it was used together with other modules. As a consequence, user and group IDs were not mapped properly. A patch has been applied to skip already configured modules. Now, the hash module can be used as the default idmap configuration back end and IDs are resolved correctly. (BZ#1350759)

4. Solution:

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

After installing this update, the smb service will be restarted automatically.

5. Bugs fixed (https://bugzilla.redhat.com/):

1350759 - idmap_hash module works incorrectly when used with other backend modules 1351260 - net ads join throws "Failed to join domain: failed to set machine kerberos encryption types: Insufficient access" 1351955 - CVE-2016-2119 samba: Client side SMB2/3 required signing can be downgraded