Bug 1488400 (CVE-2017-12150) - CVE-2017-12150 samba: Some code path don't enforce smb signing, when they should
Summary: CVE-2017-12150 samba: Some code path don't enforce smb signing, when they should
Status: CLOSED ERRATA
Alias: CVE-2017-12150
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard: impact=moderate,public=20170920,repor...
Keywords: Security
Depends On: 1491209 1491210 1491211 1491212 1491213 1491214 1491769 1493441
Blocks: 1488198
TreeView+ depends on / blocked
 
Reported: 2017-09-05 10:00 UTC by Huzaifa S. Sidhpurwala
Modified: 2019-06-11 11:13 UTC (History)
16 users (show)

(edit)
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.
Clone Of:
(edit)
Last Closed: 2019-06-08 03:24:05 UTC


Attachments (Terms of Use)


External Trackers
Tracker ID Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2017:2789 normal SHIPPED_LIVE Moderate: samba security update 2017-09-21 18:18:01 UTC
Red Hat Product Errata RHSA-2017:2790 normal SHIPPED_LIVE Moderate: samba security update 2017-09-21 18:06:48 UTC
Red Hat Product Errata RHSA-2017:2791 normal SHIPPED_LIVE Moderate: samba4 security update 2017-09-21 15:51:02 UTC
Red Hat Product Errata RHSA-2017:2858 normal SHIPPED_LIVE Moderate: samba security update 2017-10-04 09:12:56 UTC

Description Huzaifa S. Sidhpurwala 2017-09-05 10:00:33 UTC
There are several code paths where the code doesn't enforce SMB signing:

* The fixes for CVE-2015-5296 didn't apply the implied signing protection
  when enforcing encryption for commands like 'smb2mount -e', 'smbcacls -e' and
  'smbcquotas -e'.

* The python binding exported as 'samba.samba3.libsmb_samba_internal'
  doesn't make use of the "client signing" smb.conf option.

* libgpo as well as 'net ads gpo' doesn't require SMB signing when fetching
  group policies.

* Commandline tools like 'smbclient', 'smbcacls' and 'smbcquotas' allow
  a fallback to an anonymous connection when using the '--use-ccache'
  option and this happens even if SMB signing is required.

Comment 1 Huzaifa S. Sidhpurwala 2017-09-05 10:00:41 UTC
Acknowledgments:

Name: the Samba project
Upstream: Stefan Metzmacher (SerNet)

Comment 2 Huzaifa S. Sidhpurwala 2017-09-05 10:07:03 UTC
Mitigation:

The missing implied signing for 'smb2mount -e', 'smbcacls -e' and 'smbcquotas -e' can be enforced by explicitly using '--signing=required' on the commandline or "client signing = required" in smb.conf.

Comment 5 Huzaifa S. Sidhpurwala 2017-09-20 08:17:44 UTC
External References:

https://www.samba.org/samba/security/CVE-2017-12150.html

Comment 6 Huzaifa S. Sidhpurwala 2017-09-20 08:18:45 UTC
Created samba tracking bugs for this issue:

Affects: fedora-all [bug 1493441]

Comment 7 errata-xmlrpc 2017-09-21 11:51:42 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 6

Via RHSA-2017:2791 https://access.redhat.com/errata/RHSA-2017:2791

Comment 8 errata-xmlrpc 2017-09-21 14:07:48 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2017:2790 https://access.redhat.com/errata/RHSA-2017:2790

Comment 9 errata-xmlrpc 2017-09-21 14:19:28 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 6

Via RHSA-2017:2789 https://access.redhat.com/errata/RHSA-2017:2789

Comment 10 errata-xmlrpc 2017-10-04 05:13:51 UTC
This issue has been addressed in the following products:

  Red Hat Gluster Storage 3.3 for RHEL 6
  Red Hat Gluster Storage 3.3 for RHEL 7

Via RHSA-2017:2858 https://access.redhat.com/errata/RHSA-2017:2858


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