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Gentoo Linux Security Advisory                           GLSA 200609-15
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                                            https://security.gentoo.org/
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  Severity: Normal
     Title: GnuTLS: RSA Signature Forgery
      Date: September 26, 2006
      Bugs: #147682
        ID: 200609-15

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Synopsis
=======
GnuTLS fails to handle excess data which could allow an attacker to
forge a PKCS #1 v1.5 signature.

Background
=========
GnuTLS is an implementation of SSL 3.0 and TLS 1.0.

Affected packages
================
    -------------------------------------------------------------------
     Package          /  Vulnerable  /                      Unaffected
    -------------------------------------------------------------------
  1  net-libs/gnutls       < 1.4.4                            >= 1.4.4

Description
==========
verify.c fails to properly handle excess data in
digestAlgorithm.parameters field while generating a hash when using an
RSA key with exponent 3. RSA keys that use exponent 3 are commonplace.

Impact
=====
Remote attackers could forge PKCS #1 v1.5 signatures that are signed
with an RSA key, preventing GnuTLS from correctly verifying X.509 and
other certificates that use PKCS.

Workaround
=========
There is no known workaround at this time.

Resolution
=========
All GnuTLS users should update both packages:

    # emerge --sync
    # emerge --update --ask --verbose ">=net-libs/gnutls-1.4.4"

References
=========
  [ 1 ] CVE-2006-4790
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-4790

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

  https://security.gentoo.org/glsa/200609-15

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 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.

https://creativecommons.org/licenses/by-sa/2.5/