- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Gentoo Linux Security Advisory                           GLSA 201706-21
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
                                           https://security.gentoo.org/
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

 Severity: Normal
    Title: nettle: Information disclosure
     Date: June 22, 2017
     Bugs: #590484
       ID: 201706-21

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

Synopsis
========

A cache-related side channel vulnerability was found in nettle which
might allow an attacker to obtain sensitive information.

Background
==========

Nettle is a cryptographic library that is designed to fit easily in
almost any context: In cryptographic toolkits for object-oriented
languages, such as C++, Python, or Pike, in applications like lsh or
GnuPG, or even in kernel space.

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

    -------------------------------------------------------------------
     Package              /     Vulnerable     /            Unaffected
    -------------------------------------------------------------------
  1  dev-libs/nettle              < 3.2-r1                  >= 3.2-r1

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

It was found that nettle's RSA and DSA decryption code was vulnerable
to cache-related side channel attacks.

See the referenced technical paper "Cache Attacks Enable Bulk Key
Recovery on the Cloud" below for details.

Impact
======

An attacker could recover the private key from a co-located
virtual-machine instance.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All nettle users should upgrade to the latest version:

  # emerge --sync
  # emerge --ask --oneshot --verbose ">=dev-libs/nettle-3.2-r1"

References
==========

[ 1 ] CVE-2016-6489
      http://nvd.nist.gov/nvd.cfm?cvename=CVE-2016-6489
[ 2 ] Cache Attacks Enable Bulk Key Recovery on the Cloud
      https://eprint.iacr.org/2016/596.pdf

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

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

 https://security.gentoo.org/glsa/201706-21

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