[ GLSA 201001-05 ] net-snmp: Authorization bypass

[Stefan Behte <craig () gentoo org>]

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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

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