January 2007

ID: 00012
Ref: 10/2007
Date: 04 January 2007:14:34:56
Version: 1

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Title: Gentoo Linux Security Advisory: GLSA 200701-01 - DenyHosts: Denial of Service
Abstract: Tavis Ormandy of the Gentoo Linux Security Audit Team discovered that DenyHosts used an incomplete regular expression to parse failed login attempts.
Vendors affected: Gentoo
Operating systems affected: Gentoo
Applications affected: Gentoo

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Title
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Gentoo Linux Security Advisory: GLSA 200701-01 - DenyHosts: Denial of Service

Detail
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Tavis Ormandy of the Gentoo Linux Security Audit Team discovered that DenyHosts used an incomplete regular expression to parse failed login attempts.


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Gentoo Linux Security Advisory GLSA 200701-01
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http://security.gentoo.org/
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Severity: Normal
Title: DenyHosts: Denial of Service
Date: January 03, 2007
Bugs: #157163
ID: 200701-01

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Synopsis
========

DenyHosts does not correctly parse log entries, potentially causing a remote Denial of Service.

Background
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DenyHosts is designed to monitor SSH servers for repeated failed login attempts.

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

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Package / Vulnerable / Unaffected
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1 app-admin/denyhosts < 2.6 >= 2.6

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

Tavis Ormandy of the Gentoo Linux Security Audit Team discovered that DenyHosts used an incomplete regular expression to parse failed login attempts.

Impact
======

A remote unauthenticated attacker can add arbitrary hosts to the blacklist by attempting to login with a specially crafted username. An attacker may use this to prevent legitimate users from accessing a host remotely.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All DenyHosts users should upgrade to the latest version:

# emerge --sync
# emerge --ask --oneshot --verbose ">=app-admin/denyhosts-2.6"

References
==========

[ 1 ] CVE-2006-6301
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-6301

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

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

http://security.gentoo.org/glsa/glsa-200701-01.xml

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 http://bugs.gentoo.org.

License
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Copyright 2007 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