RHSA-2017:0662 - Security Advisory

Topic

An update for samba is now available for Red Hat Enterprise Linux 6.

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)

Additional Changes:

For detailed information on changes in this release, see the Red Hat Enterprise Linux 6.9 Release Notes and Red Hat Enterprise Linux 6.9 Technical Notes linked from the References section.

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 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension (for IBM z Systems) 6 s390x

Fixes

• BZ - 1327697 - schannel connections fail to the DC because netlogon credentials are not updated correctly
• BZ - 1372611 - NetAPP SMB servers don't negotiate NTLMSSP_SIGN for SESSION KEY setup
• 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 - 1413672 - BADLOCK REGRESSION: Member fails to authenticate against nt4_dc, if the member changes it secret

CVEs

• CVE-2016-2125
• CVE-2016-2126

References

• https://access.redhat.com/security/updates/classification/#moderate
• https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/6.9_Release_Notes/index.html
• https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/6.9_Technical_Notes/index.html
• https://www.samba.org/samba/security/CVE-2016-2125.html
• https://www.samba.org/samba/security/CVE-2016-2126.html