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UNIRAS Brief - 570/05 - Gentoo - Two Security Advisories



 
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   UNIRAS (UK Govt CERT) Briefing Notice - 570/05 dated 22.07.05  Time: 11:20  
  UNIRAS is part of NISCC (National Infrastructure Security Co-ordination Centre)
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  UNIRAS material is also available from its website at www.uniras.gov.uk and
         Information about NISCC is available from www.niscc.gov.uk
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Title
=====

Gentoo - Two Security Advisories:
     1.  zlib: Buffer overflow              [GLSA 200507-19] 
     2.  Shorewall: Security policy bypass  [GLSA 200507-20]


Detail
====== 

Security advisory summaries:

     1.  zlib is vulnerable to a buffer overflow which could potentially lead to
         execution of arbitrary code.

     2.  A vulnerability in Shorewall allows clients authenticated by MAC
         address filtering to bypass all other security rules.


Security advisory content follows:


1.


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Gentoo Linux Security Advisory                           GLSA 200507-19
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                                            http://security.gentoo.org/
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  Severity: High
     Title: zlib: Buffer overflow
      Date: July 22, 2005
      Bugs: #99751
        ID: 200507-19

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Synopsis
========

zlib is vulnerable to a buffer overflow which could potentially lead to
execution of arbitrary code.

Background
==========

zlib is a widely used free and patent unencumbered data compression
library.

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

    -------------------------------------------------------------------
     Package        /  Vulnerable  /                        Unaffected
    -------------------------------------------------------------------
  1  sys-libs/zlib       < 1.2.3                              >= 1.2.3

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

zlib improperly handles invalid data streams which could lead to a
buffer overflow.

Impact
======

By creating a specially crafted compressed data stream, attackers can
overwrite data structures for applications that use zlib, resulting in
arbitrary code execution or a Denial of Service.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All zlib users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=sys-libs/zlib-1.2.3"

References
==========

  [ 1 ] Full Disclosure Announcement
        http://archives.neohapsis.com/archives/fulldisclosure/2005-07/0489.html
  [ 2 ] CAN-2005-1849
        http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-1849

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

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

  http://security.gentoo.org/glsa/glsa-200507-19.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@xxxxxxxxxx or alternatively, you may file a bug at
http://bugs.gentoo.org.

License
=======

Copyright 2005 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/2.0




2.


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Gentoo Linux Security Advisory                           GLSA 200507-20
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                                            http://security.gentoo.org/
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  Severity: Low
     Title: Shorewall: Security policy bypass
      Date: July 22, 2005
      Bugs: #99398
        ID: 200507-20

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Synopsis
========

A vulnerability in Shorewall allows clients authenticated by MAC
address filtering to bypass all other security rules.

Background
==========

Shorewall is a high level tool for configuring Netfilter, the firewall
facility included in the Linux Kernel.

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

    -------------------------------------------------------------------
     Package                 /  Vulnerable  /               Unaffected
    -------------------------------------------------------------------
  1  net-firewall/shorewall       < 2.4.1                    *>= 2.2.5
                                                              >= 2.4.1

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

Shorewall fails to enforce security policies if configured with
"MACLIST_DISPOSITION" set to "ACCEPT" or "MACLIST_TTL" set to a value
greater or equal to 0.

Impact
======

A client authenticated by MAC address filtering could bypass all
security policies, possibly allowing him to gain access to restricted
services.

Workaround
==========

Set "MACLIST_TTL" to "0" and "MACLIST_DISPOSITION" to "REJECT" in the
Shorewall configuration file (usually /etc/shorewall/shorewall.conf).

Resolution
==========

All Shorewall users should upgrade to the latest available version:

    # emerge --sync
    # emerge --ask --oneshot --verbose net-firewall/shorewall

References
==========

  [ 1 ] CAN-2005-2317
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-2317
  [ 2 ] Shorewall Announcement
        http://www.shorewall.net/News.htm#20050717

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

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

  http://security.gentoo.org/glsa/glsa-200507-20.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@xxxxxxxxxx or alternatively, you may file a bug at
http://bugs.gentoo.org.

License
=======

Copyright 2005 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/2.0



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For additional information or assistance, please contact the HELP Desk by 
telephone or Not Protectively Marked information may be sent via 
EMail to: uniras@xxxxxxxxxxxx

Office Hours:
Mon - Fri: 08:30 - 17:00 Hrs
Tel: +44 (0) 870 487 0748 Ext 4511
Fax: +44 (0) 870 487 0749

Outside of Office Hours:
On Call Duty Officer:
Tel: +44 (0) 870 487 0748 and follow the prompts

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UNIRAS wishes to acknowledge the contributions of Gentoo for the information 
contained in this Briefing. 
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This Briefing contains the information released by the original author. Some 
of the information may have changed since it was released. If the vulnerability 
affects you, it may be prudent to retrieve the advisory from the canonical site 
to ensure that you receive the most current information concerning that problem.

Reference to any specific commercial product, process, or service by trade 
name, trademark manufacturer, or otherwise, does not constitute or imply 
its endorsement, recommendation, or favouring by UNIRAS or NISCC.  The views 
and opinions of authors expressed within this notice shall not be used for 
advertising or product endorsement purposes.

Neither UNIRAS or NISCC shall also accept responsibility for any errors 
or omissions contained within this briefing notice. In particular, they shall 
not be liable for any loss or damage whatsoever, arising from or in connection 
with the usage of information contained within this notice.

UNIRAS is a member of the Forum of Incident Response and Security Teams (FIRST) 
and has contacts with other international Incident Response Teams (IRTs) in 
order to foster cooperation and coordination in incident prevention, to prompt 
rapid reaction to incidents, and to promote information sharing amongst its 
members and the community at large. 
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<End of UNIRAS Briefing>

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