RHSA-2017:2789 - 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):

• 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)
• It was found that samba did not enforce "SMB signing" when certain configuration options were enabled. A remote attacker could launch a man-in-the-middle attack and retrieve information in plain-text. (CVE-2017-12150)
• An information leak flaw was found in the way SMB1 protocol was implemented by Samba. A malicious client could use this flaw to dump server memory contents to a file on the samba share or to a shared printer, though the exact area of server memory cannot be controlled by the attacker. (CVE-2017-12163)

Red Hat would like to thank the Samba project for reporting CVE-2017-2619 and CVE-2017-12150 and Yihan Lian and Zhibin Hu (Qihoo 360 GearTeam), Stefan Metzmacher (SerNet), and Jeremy Allison (Google) for reporting CVE-2017-12163. Upstream acknowledges Jann Horn (Google) as the original reporter of CVE-2017-2619; and Stefan Metzmacher (SerNet) as the original reporter of CVE-2017-12150.

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 - 1429472 - CVE-2017-2619 samba: symlink race permits opening files outside share directory
• BZ - 1488400 - CVE-2017-12150 samba: Some code path don't enforce smb signing, when they should
• BZ - 1491206 - CVE-2017-12163 Samba: Server memory information leak over SMB1

CVEs

• CVE-2017-12150
• CVE-2017-12163
• CVE-2017-2619

References

• https://access.redhat.com/security/updates/classification/#moderate