Bug 1488400 – CVE-2017-12150 samba: Some code path don't enforce smb signing, when they should

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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:	NEW

Aliases:	CVE-2017-12150

Product:	Security Response
Classification:	Other
Component:	vulnerability (Show other bugs)
Sub Component:
Version:	unspecified
Hardware:	All Linux

Priority	medium Severity medium
Target Milestone:	---
Target Release:	---
Assigned To:	Red Hat Product Security
QA Contact:
Docs Contact:

URL:
Whiteboard:	impact=moderate,public=20170920,repor...
Keywords:	Security

Depends On:	1491209 1491210 1491211 1491212 1491213 1491214 1491769 1493441
Blocks:	1488198
	Show dependency tree / graph

Reported:	2017-09-05 06:00 EDT by Huzaifa S. Sidhpurwala
Modified:	2018-07-26 10:11 EDT (History)
CC List:	17 users (show)

See Also:
Fixed In Version:	samba 4.6.8, samba 4.5.14, samba 4.4.16, samba 4.7.0
Doc Type:	If docs needed, set a value
Doc Text:	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.
Story Points:	---
Clone Of:
Environment:
Last Closed:
Type:	---
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

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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 14:18:01 EDT
Red Hat Product Errata	RHSA-2017:2790	normal	SHIPPED_LIVE	Moderate: samba security update	2017-09-21 14:06:48 EDT
Red Hat Product Errata	RHSA-2017:2791	normal	SHIPPED_LIVE	Moderate: samba4 security update	2017-09-21 11:51:02 EDT
Red Hat Product Errata	RHSA-2017:2858	normal	SHIPPED_LIVE	Moderate: samba security update	2017-10-04 05:12:56 EDT

Groups: None (edit)

Description Huzaifa S. Sidhpurwala 2017-09-05 06:00:33 EDT

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 06:00:41 EDT

Acknowledgments:

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

Comment 2 Huzaifa S. Sidhpurwala 2017-09-05 06:07:03 EDT

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 04:17:44 EDT

External References:

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

Comment 6 Huzaifa S. Sidhpurwala 2017-09-20 04:18:45 EDT

Created samba tracking bugs for this issue:

Affects: fedora-all [bug 1493441]

Comment 7 errata-xmlrpc 2017-09-21 07:51:42 EDT

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 10:07:48 EDT

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 10:19:28 EDT

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 01:13:51 EDT

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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