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Gentoo Linux Security Advisory                           GLSA 201001-05
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                                            http://security.gentoo.org/
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  Severity: Normal
     Title: net-snmp: Authorization bypass
      Date: January 13, 2010
      Bugs: #250429
        ID: 201001-05

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Synopsis
========

A remote attacker can bypass the tcp-wrappers client authorization in
net-snmp.

Background
==========

net-snmp bundles software for generating and retrieving SNMP data.

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

    -------------------------------------------------------------------
     Package                /   Vulnerable   /              Unaffected
    -------------------------------------------------------------------
  1  net-analyzer/net-snmp     < 5.4.2.1-r1              >= 5.4.2.1-r1

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

The netsnmp_udp_fmtaddr() function (snmplib/snmpUDPDomain.c), when
using TCP wrappers for client authorization, does not properly parse
hosts.allow rules.

Impact
======

A remote, unauthenticated attacker could bypass the ACL filtering,
possibly resulting in the execution of arbitrary SNMP queries.

Workaround
==========

If possible, protect net-snmp with custom iptables rules:

    iptables -s [client] -d [host] -p udp --dport 161 -j ACCEPT
    iptables -s 0.0.0.0/0 -d [host] -p udp --dport 161 -j DROP

Resolution
==========

All net-snmp users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=net-analyzer/net-snmp-5.4.2.1-r1"

References
==========

  [ 1 ] CVE-2008-6123
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-6123

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

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

  http://security.gentoo.org/glsa/glsa-201001-05.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
https://bugs.gentoo.org.

License
=======

Copyright 2010 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