[ GLSA 200603-15 ] Crypt::CBC: Insecure initialization vector

[Stefan Cornelius <dercorny () gentoo org>]

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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

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