Bug 1488400 (CVE-2017-12150)

Summary:	CVE-2017-12150 samba: Some code path don't enforce smb signing, when they should
Product:	[Other] Security Response	Reporter:	Huzaifa S. Sidhpurwala <huzaifas>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	abokovoy, anoopcs, asn, gdeschner, jarrpa, jlayton, kyoshida, lmohanty, madam, rhs-smb, sbose, security-response-team, sisharma, ssaha, ssorce, vbellur
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
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:	2019-06-08 03:24:05 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1491209, 1491210, 1491211, 1491212, 1491213, 1491214, 1491769, 1493441
Bug Blocks:	1488198

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