django-debreach

Extra mitigation against the BREACH attack for Django projects.

Note (that as of version 4.2 Django) includes this protection natively and this library is not needed.

django-debreach provides additional protection to Django's built in CSRF token masking by randomising the content length of each response. This is achieved by adding a random string of between 12 and 25 characters as a comment to the end of the HTML content. Note that this will only be applied to responses with a content type of text/html.

When combined with the built-in mitigations in Django and rate limiting (either in your web-server, or by using something like django-ratelimit), the techniques here should provide a fairly comprehensive protection against the BREACH attack.

Installation & Usage

Install from PyPI using:

$ pip install django-debreach

To enable content length modification for all responses, add the debreach.middleware.RandomCommentMiddleware to the start of your middleware, but after the GzipMiddleware if you are using that.:

MIDDLEWARE_CLASSES = (
    'debreach.middleware.RandomCommentMiddleware',
    ...
)

or:

MIDDLEWARE_CLASSES = (
    'django.middleware.gzip.GzipMiddleware',
    'debreach.middleware.RandomCommentMiddleware',
    ...
)

If you wish to disable this feature for selected views, simply apply the debreach.decorators.random_comment_exempt decorator to the view.

If you only want to protect a subset of views with content length modification then it may be easier to not use the middleware, but to selectively apply the debreach.decorators.append_random_comment decorator to the views you want protected.

Python 2 and Django < 2.0 support

Version 2.0.0 drops all support for Python 2 and Django < 2.0. If you need support for those versions continue using django-debreach>=1.5.2,<2.0.