- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Gentoo Linux Security Advisory                           GLSA 201701-22
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
                                           https://security.gentoo.org/
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

 Severity: Normal
    Title: NGINX: Privilege escalation
     Date: January 11, 2017
     Bugs: #605008
       ID: 201701-22

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Synopsis
========

Gentoo's NGINX ebuilds are vulnerable to privilege escalation due to
the way log files are handled.

Background
==========

nginx is a robust, small, and high performance HTTP and reverse proxy
server.

Affected packages
=================

    -------------------------------------------------------------------
     Package              /     Vulnerable     /            Unaffected
    -------------------------------------------------------------------
  1  www-servers/nginx          < 1.10.2-r3              >= 1.10.2-r3

Description
===========

It was discovered that Gentoo's default NGINX installation applied
similar problematic permissions on "/var/log/nginx" as Debian
(DSA-3701) and is therefore vulnerable to the same attack described in
CVE-2016-1247.

Impact
======

A local attacker, who either is already NGINX's system user or belongs
to NGINX's group, could potentially escalate privileges.

Workaround
==========

Ensure that no untrusted user can create files in directories which are
used by NGINX (or an NGINX vhost) to store log files.

Resolution
==========

All NGINX users should upgrade to the latest ebuild revision:

  # emerge --sync
  # emerge --ask --oneshot --verbose ">=www-servers/nginx-1.10.2-r3"

References
==========

[ 1 ] CVE-2016-1247
      http://nvd.nist.gov/nvd.cfm?cvename=CVE-2016-1247
[ 2 ] DSA-3701
      https://www.debian.org/security/2016/dsa-3701
[ 3 ] Technical analysis
      https://legalhackers.com/advisories/Nginx-Exploit-Deb-Root-PrivEsc-=
CVE-2016-1247.html

Availability
============

This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:

 https://security.gentoo.org/glsa/201701-22

Concerns?
=========

Security is a primary focus of Gentoo Linux and ensuring the
confidentiality and security of our users' machines is of utmost
importance to us. Any security concerns should be addressed to
security@gentoo.org or alternatively, you may file a bug at
https://bugs.gentoo.org.

License
=======

Copyright 2017 Gentoo Foundation, Inc; referenced text
belongs to its owner(s).

The contents of this document are licensed under the
Creative Commons - Attribution / Share Alike license.

http://creativecommons.org/licenses/by-sa/2.5