Puppet users - Sep 2011 - Announce: New Puppet releases due to CVE-2011-3848 [security]

There has been a vulnerability discovered in Puppet (CVE-2011-3848).


# Recommended Action #

Puppet Labs has an updated version of Puppet available at the
following locations:

* http://puppetlabs.com/security/hotfixes
* http://puppetlabs.com/downloads/puppet


The fixed versions are 2.6.10 in the 2.6.x branch and 2.7.4 in the
2.7.x branch.

The hotfixes page also contains updated Puppet packages for Puppet
Enterprise versions 1.0, 1.1 and 1.2.x.


Puppet Labs has been coordinating with Debian, Ubuntu, EPEL and
OpenSuSE maintainers.  We expect new packages (with a patch backported
in many cases) to be released as soon as possible.


Separate release announcements for Puppet 2.6.10 and 2.7.4 are pending.



# Explanation  #


   Kristian Erik Hermansen <kristian.hermansen@gmail.com> reported that
   an unauthenticated directory traversal could drop any valid X.509
   Certificate Signing Request at any location on disk, with the
   privileges of the Puppet Master application.  This was found in the
   2.7 series of Puppet, but the underlying vulnerability existed in
   earlier releases and could be accessed with different hostile inputs.

   There are also some additional quirks of input handling that make it
   easier to obfuscate the input.

   This exploits an input quirk where the "key" in the URI is
   double-decoded; this would also work for a single URI-encoded input
   string.

   On 2.6 this is ignored, but the CN in the Subject of the CSR is used
   in the same way, and could be exploited to drop the CSR content at an
   arbitrary location on disk.  The suffix ".pem" is always appended
to the location.


   In the 0.25 series the same CN-based injection can occur, as the
   underlying flaw still exists.

   In all cases this requires that the input data can be loaded through
   OpenSSL as a CSR, and will fail before touching disk if that is not
   valid data.


   Be aware that both double-encoded and single-encoded URI patterns will
   work, equivalently, in Puppet 2.7.  No URI decoding is done on the CN
   of the CSR Subject.



# Commit message for fix #

I have included patches for the 0.25.x, 2.6.x, and 2.7.x branches.

  Author: Daniel Pittman <daniel@puppetlabs.com> Date:   Sat Sep
  24 12:44:20 2011 -0700

  Resist directory traversal attacks through indirections.

  In various versions of Puppet it was possible to cause a directory
  traversal attack through the SSLFile indirection base class.
  This was variously triggered through the user-supplied key, or
  the Subject of the certificate, in the code.

  Now, we detect bad patterns down in the base class for our
  indirections, and fail hard on them.  This reduces the attack
  surface with as little disruption to the overall codebase as
  possible, making it suitable to deploy as part of older, stable
  versions of Puppet.

  In the long term we will also address this higher up the stack,
  to prevent these problems from reoccurring, but for now this
  will suffice.

  Huge thanks to Kristian Erik Hermansen <kristian.hermansen@gmail.com>
  for the responsible disclosure, and useful analysis, around
  this defect.

  Signed-off-by: Daniel Pittman <daniel@puppetlabs.com>




# Note for 0.25 users #

If you''re still shipping/using 0.25, we have supplied a patch to
several distro maintainers that
applies cleanly to our git tree, but will not be releasing any
upstream source of it.





If you have any questions or need additional clarification on
anything, please respond to security@puppetlabs.com.


Thanks, Michael Stahnke
Release Manager -- Puppet Labs

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