Moderate: samba security and bug fix update

Synopsis

Moderate: samba security and bug fix update

Type/Severity

Security Advisory: Moderate

Topic

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.

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):

  • It was found that Samba always requested forwardable tickets when using Kerberos authentication. A service to which Samba authenticated using Kerberos could subsequently use the ticket to impersonate Samba to other services or domain users. (CVE-2016-2125)
  • A flaw was found in the way Samba handled PAC (Privilege Attribute Certificate) checksums. A remote, authenticated attacker could use this flaw to crash the winbindd process. (CVE-2016-2126)
  • A race condition was found in samba server. A malicious samba client could use this flaw to access files and directories, in areas of the server file system not exported under the share definitions. (CVE-2017-2619)

Red Hat would like to thank the Samba project for reporting CVE-2017-2619. Upstream acknowledges Jann Horn (Google) as the original reporter of CVE-2017-2619.

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.

Affected Products

  • Red Hat Enterprise Linux Server 7 x86_64
  • Red Hat Enterprise Linux Server - Extended Update Support 7.6 x86_64
  • Red Hat Enterprise Linux Server - Extended Update Support 7.5 x86_64
  • Red Hat Enterprise Linux Server - Extended Update Support 7.4 x86_64
  • Red Hat Enterprise Linux Server - Extended Update Support 7.3 x86_64
  • Red Hat Enterprise Linux Server - AUS 7.6 x86_64
  • Red Hat Enterprise Linux Server - AUS 7.4 x86_64
  • Red Hat Enterprise Linux Workstation 7 x86_64
  • Red Hat Enterprise Linux Desktop 7 x86_64
  • Red Hat Enterprise Linux for IBM z Systems 7 s390x
  • Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.6 s390x
  • Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.5 s390x
  • Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.4 s390x
  • Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.3 s390x
  • Red Hat Enterprise Linux for Power, big endian 7 ppc64
  • Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.6 ppc64
  • Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.5 ppc64
  • Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.4 ppc64
  • Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.3 ppc64
  • Red Hat Enterprise Linux for Scientific Computing 7 x86_64
  • Red Hat Enterprise Linux Resilient Storage (for RHEL Server) 7 x86_64
  • Red Hat Enterprise Linux Resilient Storage (for RHEL Server) - Extended Update Support 7.6 x86_64
  • Red Hat Enterprise Linux Resilient Storage (for RHEL Server) - Extended Update Support 7.5 x86_64
  • Red Hat Enterprise Linux Resilient Storage (for RHEL Server) - Extended Update Support 7.4 x86_64
  • Red Hat Enterprise Linux Resilient Storage (for RHEL Server) - Extended Update Support 7.3 x86_64
  • Red Hat Enterprise Linux EUS Compute Node 7.6 x86_64
  • Red Hat Enterprise Linux EUS Compute Node 7.5 x86_64
  • Red Hat Enterprise Linux EUS Compute Node 7.4 x86_64
  • Red Hat Enterprise Linux EUS Compute Node 7.3 x86_64
  • Red Hat Enterprise Linux Server - AUS 7.3 x86_64
  • Red Hat Enterprise Linux for Power, little endian 7 ppc64le
  • Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.6 ppc64le
  • Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.5 ppc64le
  • Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.4 ppc64le
  • Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.3 ppc64le
  • Red Hat Enterprise Linux Server - TUS 7.6 x86_64
  • Red Hat Enterprise Linux Server - TUS 7.3 x86_64
  • Red Hat Enterprise Linux Server (for IBM Power LE) - Update Services for SAP Solutions 7.6 ppc64le
  • Red Hat Enterprise Linux Server (for IBM Power LE) - Update Services for SAP Solutions 7.4 ppc64le
  • Red Hat Enterprise Linux Server (for IBM Power LE) - Update Services for SAP Solutions 7.3 ppc64le
  • Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.6 x86_64
  • Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.4 x86_64
  • Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.3 x86_64

Fixes

  • BZ - 1403114 - CVE-2016-2125 samba: Unconditional privilege delegation to Kerberos servers in trusted realms
  • BZ - 1403115 - CVE-2016-2126 samba: Flaws in Kerberos PAC validation can trigger privilege elevation
  • BZ - 1429472 - CVE-2017-2619 samba: symlink race permits opening files outside share directory

CVEs

References