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Gentoo Linux Security Advisory                           GLSA 200609-17
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                                            https://security.gentoo.org/
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  Severity: Normal
     Title: OpenSSH: Denial of Service
      Date: September 27, 2006
      Bugs: #148228
        ID: 200609-17

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Synopsis
=======
A flaw in the OpenSSH daemon allows remote unauthenticated attackers to
cause a Denial of Service.

Background
=========
OpenSSH is a free suite of applications for the SSH protocol, developed
and maintained by the OpenBSD project.

Affected packages
================
    -------------------------------------------------------------------
     Package           /   Vulnerable   /                   Unaffected
    -------------------------------------------------------------------
  1  net-misc/openssh      < 4.3_p2-r5                    >= 4.3_p2-r5

Description
==========
Tavis Ormandy of the Google Security Team discovered a Denial of
Service vulnerability in the SSH protocol version 1 CRC compensation
attack detector.

Impact
=====
A remote unauthenticated attacker may be able to trigger excessive CPU
usage by sending a pathological SSH message, denying service to other
legitimate users or processes.

Workaround
=========
The system administrator may disable SSH protocol version 1 in
/etc/ssh/sshd_config.

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

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=net-misc/openssh-4.3_p2-r3"

References
=========
  [ 1 ] CVE-2006-4924
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-4924

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

  https://security.gentoo.org/glsa/200609-17

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 2006 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/