Summary
=======

  Subversion's mod_authz_svn does not properly restrict anonymous
  access in some mixed anonymous/authenticated environments when using
  Apache httpd 2.4.  The result is that anonymous access may be possible
  to files for which only authenticated access should be possible.

Known vulnerable
================

  Apache httpd 2.4.0 to 2.4.12
  Apache Subversion 1.8.0 to 1.8.13
  Apache Subversion 1.7.0 to 1.7.20

  Servers are vulnerable if either httpd or Subversion is as listed.

  Subversion 1.6 does not build with httpd 2.4 and servers using
  httpd 2.2 are not vulnerable.  Servers that are configured to deny
  anonymous access are not vulnerable.

Known fixed
===========

  Apache httpd 2.4.13
  Apache Subversion 1.8.14 and 1.7.21

  Both httpd and Subversion need to be updated.

Details
=======

  If you have a Subversion repository configured for anonymous read
  that has mod_authz_svn configured such that some portion of the
  repository is hidden from an anonymous user, then in certain cases
  when Subversion is used with Apache httpd 2.4.x the file contents of
  the repository may be exposed to someone who knows the path name
  within the repository.  The protected files and directories will not
  show on directory listings.  Protected directories that do not show
  in their parent will return an empty directory listing rather than a
  403 error.  Protected files will return the full content of the
  file.  Specifically the conditions required for this to happen is
  that there needs to be a <Directory> block for the DocumentRoot
  allowing access to everyone (e.g. Require all granted) and "Satisfy
  any" must not be set.  This sort of configuration is included in the
  default httpd.conf that `make install` provides and is fairly
  standard.

Severity
========

  CVSSv2 Base Score: 4.3
  CVSSv2 Base Vector: AV:N/AC:M/Au:N/C:P/I:N/A:N

  The repository needs to be configured with mixed anonymous and
  authenticated path-based authz and the the attacker needs to know
  the paths to files in the repository that require authentication.

Recommendations
===============

  All users of mixed anonymous/authenticated authz to upgrade Apache
  and Subversion.

  As a workaround disable mixed anonymous/authenticated authz.

References
==========

  CVE-2015-3184 (Subversion)
  CVE-2015-3185 (httpd)

Reported by
===========

  C. Michael Pilato, CollabNet