- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Gentoo Linux Security Advisory                           GLSA 201911-01
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
                                           https://security.gentoo.org/
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

 Severity: Normal
    Title: OpenSSH: Integer overflow
     Date: November 07, 2019
     Bugs: #697046
       ID: 201911-01

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

Synopsis
=======
An integer overflow in OpenSSH might allow an attacker to execute
arbitrary code.

Background
=========
OpenSSH is a complete SSH protocol implementation that includes SFTP
client and server support.

Affected packages
================
    -------------------------------------------------------------------
     Package              /     Vulnerable     /            Unaffected
    -------------------------------------------------------------------
  1  net-misc/openssh           >= 8.0_p1-r2             >= 8.0_p1-r4 

Description
==========
OpenSSH, when built with "xmss" USE flag enabled, has a
pre-authentication integer overflow if a client or server is configured
to use a crafted XMSS key.

NOTE: This USE flag is disabled by default!

Impact
=====
A remote attacker could connect to a vulnerable OpenSSH server using a
special crafted XMSS key possibly resulting in execution of arbitrary
code with the privileges of the process or a Denial of Service
condition.

Workaround
=========
Disable XMSS key type.

Resolution
=========
All OpenSSH users should upgrade to the latest version:

  # emerge --sync
  # emerge --ask --oneshot -v ">=net-misc/openssh/openssh-8.0_p1-r4"

References
=========
[ 1 ] CVE-2019-16905
      https://nvd.nist.gov/vuln/detail/CVE-2019-16905

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

 https://security.gentoo.org/glsa/201911-01

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 2019 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.

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