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Gentoo Linux Security Advisory GLSA 201911-01
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https://security.gentoo.org/
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Severity: Normal
Title: OpenSSH: Integer overflow
Date: November 07, 2019
Bugs: #697046
ID: 201911-01

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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

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