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Gentoo Linux Security Advisory                           GLSA 200603-15
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                                            http://security.gentoo.org/
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  Severity: Low
     Title: Crypt::CBC: Insecure initialization vector
      Date: March 17, 2006
      Bugs: #126048
        ID: 200603-15

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Synopsis
========

Crypt::CBC uses an insecure initialization vector, potentially
resulting in a weaker encryption.

Background
==========

Crypt::CBC is a Perl module to encrypt data using cipher block chaining
(CBC).

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

    -------------------------------------------------------------------
     Package             /  Vulnerable  /                   Unaffected
    -------------------------------------------------------------------
  1  dev-perl/crypt-cbc       < 2.17                           >= 2.17

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

Lincoln Stein discovered that Crypt::CBC fails to handle 16 bytes long
initializiation vectors correctly when running in the RandomIV mode,
resulting in a weaker encryption because the second part of every block
will always be encrypted with zeros if the blocksize of the cipher is
greater than 8 bytes.

Impact
======

An attacker could exploit weak ciphertext produced by Crypt::CBC to
bypass certain security restrictions or to gain access to sensitive
data.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All Crypt::CBC users should upgrade to the latest available version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=dev-perl/crypt-cbc-2.17"

References
==========

  [ 1 ] CVE-2006-0898
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-0898

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

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

  http://security.gentoo.org/glsa/glsa-200603-15.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 2006 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