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Gentoo Linux Security Advisory                           GLSA 201611-19
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                                           https://security.gentoo.org/
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 Severity: Normal
    Title: Tar: Extract pathname bypass
     Date: November 22, 2016
     Bugs: #598334
       ID: 201611-19

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Synopsis
========

A path traversal attack in Tar may lead to the remote execution of
arbitrary code.

Background
==========

The Tar program provides the ability to create and manipulate tar
archives.

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

    -------------------------------------------------------------------
     Package              /     Vulnerable     /            Unaffected
    -------------------------------------------------------------------
  1  app-arch/tar                < 1.29-r1                 >= 1.29-r1

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

Tar attempts to avoid path traversal attacks by removing offending
parts of the element name at extract. This sanitizing leads to a
vulnerability where the attacker can bypass the path name(s) specified
on the command line.

Impact
======

The attacker can create a crafted tar archive that, if extracted by the
victim, replaces files and directories the victim has access to in the
target directory, regardless of the path name(s) specified on the
command line.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All Tar users should upgrade to the latest version:

  # emerge --sync
  # emerge --ask --oneshot --verbose ">=app-arch/tar-1.29-r1"

References
==========

[ 1 ] CVE-2016-6321
      http://nvd.nist.gov/nvd.cfm?cvename=CVE-2016-6321

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

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

 https://security.gentoo.org/glsa/201611-19

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 2016 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