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Gentoo Linux Security Advisory                           GLSA 200410-31
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                                            http://security.gentoo.org/
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  Severity: Low
     Title: Archive::Zip: Virus detection evasion
      Date: October 29, 2004
      Bugs: #68616
        ID: 200410-31

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Synopsis
========

Email virus scanning software relying on Archive::Zip can be fooled
into thinking a ZIP attachment is empty while it contains a virus,
allowing detection evasion.

Background
==========

Archive::Zip is a Perl module containing functions to handle ZIP
archives.

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

    -------------------------------------------------------------------
     Package               /  Vulnerable  /                 Unaffected
    -------------------------------------------------------------------
  1  dev-perl/Archive-Zip       < 1.14                         >= 1.14

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

Archive::Zip can be used by email scanning software (like amavisd-new)
to uncompress attachments before virus scanning. By modifying the
uncompressed size of archived files in the global header of the ZIP
file, it is possible to fool Archive::Zip into thinking some files
inside the archive have zero length.

Impact
======

An attacker could send a carefully crafted ZIP archive containing a
virus file and evade detection on some email virus-scanning software
relying on Archive::Zip for decompression.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All Archive::Zip users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=dev-perl/Archive-Zip-1.14"

References
==========

  [ 1 ] iDEFENSE Security Advisory 10.18.04
        http://www.idefense.com/application/poi/display?id=153
  [ 2 ] rt.cpan.org bug #8077
        http://rt.cpan.org/NoAuth/Bug.html?id=8077

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

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

  http://security.gentoo.org/glsa/glsa-200410-31.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
=======

Copyright 2004 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/1.0