51 lines
2.4 KiB
Plaintext
51 lines
2.4 KiB
Plaintext
|
==========================
|
||
|
|
Django 1.5.3 release notes
|
||
|
|
==========================
|
||
|
|
|
||
|
|
*September 10, 2013*
|
||
|
|
|
||
|
|
This is Django 1.5.3, the third release in the Django 1.5 series. It addresses
|
||
|
|
one security issue and also contains an opt-in feature to enhance the security
|
||
|
|
of :mod:`django.contrib.sessions`.
|
||
|
|
|
||
|
|
Directory traversal vulnerability in :ttag:`ssi` template tag
|
||
|
|
-------------------------------------------------------------
|
||
|
|
|
||
|
|
In previous versions of Django it was possible to bypass the
|
||
|
|
:setting:`ALLOWED_INCLUDE_ROOTS` setting used for security with the :ttag:`ssi`
|
||
|
|
template tag by specifying a relative path that starts with one of the allowed
|
||
|
|
roots. For example, if ``ALLOWED_INCLUDE_ROOTS = ("/var/www",)`` the following
|
||
|
|
would be possible:
|
||
|
|
|
||
|
|
.. code-block:: html+django
|
||
|
|
|
||
|
|
{% ssi "/var/www/../../etc/passwd" %}
|
||
|
|
|
||
|
|
In practice this is not a very common problem, as it would require the template
|
||
|
|
author to put the :ttag:`ssi` file in a user-controlled variable, but it's
|
||
|
|
possible in principle.
|
||
|
|
|
||
|
|
Mitigating a remote-code execution vulnerability in :mod:`django.contrib.sessions`
|
||
|
|
----------------------------------------------------------------------------------
|
||
|
|
|
||
|
|
:mod:`django.contrib.sessions` currently uses :mod:`pickle` to serialize
|
||
|
|
session data before storing it in the backend. If you're using the :ref:`signed
|
||
|
|
cookie session backend<cookie-session-backend>` and :setting:`SECRET_KEY` is
|
||
|
|
known by an attacker (there isn't an inherent vulnerability in Django that
|
||
|
|
would cause it to leak), the attacker could insert a string into his session
|
||
|
|
which, when unpickled, executes arbitrary code on the server. The technique for
|
||
|
|
doing so is simple and easily available on the internet. Although the cookie
|
||
|
|
session storage signs the cookie-stored data to prevent tampering, a
|
||
|
|
:setting:`SECRET_KEY` leak immediately escalates to a remote code execution
|
||
|
|
vulnerability.
|
||
|
|
|
||
|
|
This attack can be mitigated by serializing session data using JSON rather
|
||
|
|
than :mod:`pickle`. To facilitate this, Django 1.5.3 introduces a new setting,
|
||
|
|
:setting:`SESSION_SERIALIZER`, to customize the session serialization format.
|
||
|
|
For backwards compatibility, this setting defaults to using :mod:`pickle`.
|
||
|
|
While JSON serialization does not support all Python objects like :mod:`pickle`
|
||
|
|
does, we highly recommend switching to JSON-serialized values. Also,
|
||
|
|
as JSON requires string keys, you will likely run into problems if you are
|
||
|
|
using non-string keys in ``request.session``. See the
|
||
|
|
:ref:`session_serialization` documentation for more details.
|