Gentoo: GLSA-202004-08: libssh: Denial of Service

Date 10 Apr 2020

Category Gentoo Linux Distribution - Security Advisories

522

Posted By LinuxSecurity Advisories

A vulnerability in libssh could allow a remote attacker to cause a Denial of Service condition.

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Gentoo Linux Security Advisory                           GLSA 202004-08
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                                           https://security.gentoo.org/
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 Severity: Low
    Title: libssh: Denial of Service
     Date: April 10, 2020
     Bugs: #716788
       ID: 202004-08

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Synopsis
========

A vulnerability in libssh could allow a remote attacker to cause a
Denial of Service condition.

Background
==========

libssh is a multiplatform C library implementing the SSHv2 protocol on
client and server side.

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

    -------------------------------------------------------------------
     Package              /     Vulnerable     /            Unaffected
    -------------------------------------------------------------------
  1  net-libs/libssh              < 0.9.4                    >= 0.9.4

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

It was discovered that libssh could crash when AES-CTR ciphers are
used.

Impact
======

A remote attacker running a malicious client or server could possibly
crash the counterpart implemented with libssh and cause a Denial of
Service condition.

Workaround
==========

Disable AES-CTR ciphers. If you implement a server using libssh it is
recommended to use a prefork model so each session runs in an own
process.

Resolution
==========

All libssh users should upgrade to the latest version:

  # emerge --sync
  # emerge --ask --oneshot --verbose ">=net-libs/libssh-0.9.4"

References
==========

[ 1 ] CVE-2020-1730
      https://nvd.nist.gov/vuln/detail/CVE-2020-1730

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

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

 https://security.gentoo.org/glsa/202004-08

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
This email address is being protected from spambots. You need JavaScript enabled to view it. or alternatively, you may file a bug at
https://bugs.gentoo.org.

License
=======

Copyright 2020 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