Django + CloudFront caching without HTTP_REFERER - django

We use django 1.8. on backend with default authorization that runs on elasticbeanstalk and AWS CloudFront to cache app pages on CDN level. The problem is that we want to whitelist as few http headers as possible to minimize keys amount and maximize hit rate. One of the headers that varies a lot and we would prefer to exclude is HTTP_REFERER. On business level we are fine with resolving referer through js by using document.referer and that sending it to server with ajax calls.
The problem: csrf login, registration and other default django authentification apps require HTTP_REFERER when used on website on https protocol.
One of the solutions I found is to move all auth pages to separate behaviours and proxy all headers there. Are there any other ways to make such set up work?

I don't think there's another solution then the one you mention, use a separate behavior.
I usually use rest api calls from frontend to backend so I don't need the Referer header there.
Then add an extra behavior for /admin/ where I do forward Referer.

Related

Is there any way to Block request from Postman or other apps to call Restful API

Infra of system
Expected:
I want to block requests, which is not from Server FE (domain.com)
Ex: Users make request from another apps such as Postman -> it will response 403, message access denied.
I used the rules of ALB, it works but users can cheat on Postman
Also I use AWS WAF to detect request. But it's not work.
Is there any way to block request from Postman or another apps?
We can generate secret_key and check between Server FE and Server BE. But users can see it on Headers and simulator the headers on Postman and call API success.
Current Solution:
I use Rule of Application Load Balancer to check Host and Origin. But users can add these params on Postman and request success.
Rule ALB
When I add Origin matching value (set on ALB) -> We can request successful
Postman success
Postman denied
Users can cheat and call API success.
Thanks for reading. Please help me give any solution for this one. Thanks a lot.
No. HTTP servers have no way to know what client is being used to make any HTTP request. Any HTTP client (Browsers, PostMan, curl, whatever) is capable of making exactly the same requests as each other.
The user-agent header is a superficial way to do this, but it's easy enough for PostMan or any other HTTP client to spoof the user-agent header to one that makes the request look like it is coming from a web browser agent.
You can only make it more challenging to do so. Some examples to thwart this behavior includes using tools like Google captcha or CloudFlare browser integrity check, but they're not bulletproof and ultimately aren't 100% effective at stopping people from using tools/automation to access your site in unintended ways. At the end of the day, you're limited to what can be done with HTTP, and PostMan can do everything at the HTTP layer.

AWS API Gateway Custom Domain not passing the user-agent

I have a custom domain example.com that is redirecting to my API gateway api-example.com, but it doesn't seem to pass the user-agent field, all my user-agent values are AmazonAPIGateway_5rfp2g9h9b.
If I call directly the api-example.com then it works fine, but if I call example.com, doesn't work.
Any idea on how I could pass the correct user-agent HTTP Header?
Thanks
It’s not clear what you mean by redirect or the domains you have listed, so you have two custom domains ? And if so how did you do that, Cloudfront with a custom origin? And what type of integration request do you have? Is this a REST or HTTP API? Probably why you are getting down voted because you don’t have any detail and the domains don’t make sense.
Either way in your API make sure you have the user-angent field defined where it is applicable:
Request Part of your API, and make sure your integration request is forwarding this header
Likewise make sure Cloudfront forwards the ‘user-agent’ header, that it is also whitelisted if you are using Cloudfront
Note this header comes from your Web browser or SDK being used sometimes sets this too. So if you don’t set this header for whatever reason that could be a problem, I don’t know if for example when you say from this domain that means you are using a hosted website, and another means making a request from Postman, etc.
Short answer: Validate the contents of your header
Ref AWS user-agent redirect here.. as listed below.
Redirects and HTTP user-agents:
..Programs that use the Amazon S3 REST API should handle redirects either at the application layer or the HTTP layer. Many HTTP client libraries and user agents can be configured to correctly handle redirects automatically; however, many others have incorrect or incomplete redirect implementations.
Before you rely on a library to fulfill the redirect requirement, test the following cases:
Verify all HTTP request headers are correctly included in the redirected request (the second request after receiving a redirect) including HTTP standards such as Authorization and Date.
Verify non-GET redirects, such as PUT and DELETE, work correctly.
Verify large PUT requests follow redirects correctly.
Verify PUT requests follow redirects correctly if the 100-continue response takes a long time to arrive.
HTTP user-agents that strictly conform to RFC 2616 might require explicit confirmation before following a redirect when the HTTP request method is not GET or HEAD. It is generally safe to follow redirects generated by Amazon S3 automatically, as the system will issue redirects only to hosts within the amazonaws.com domain and the effect of the redirected request will be the same as that of the original request...
Optional/Additional help, I was trying to understand your description, if you're going across domains, thats CORS.
Please consider CORS which you seem to be missing, please see configuration
here.
Also very important you Enabling CORS support for a resource and its methods does not recursively enable it for child resources and their methods.
If you want to setup your custom header for
user-agent
Setup CORS in Console
How to setup from console under the resources enable the CORS.
Setup your Headers
As a last step you have to REdeploy to a stage, for the settings to take effect!

How to handle conflicting basic auth from NGINX reverse proxy with JWT auth from Django?

we have a standard Django web app running behind a reverse proxy.
I want to setup a two layer authentification : one from the nginx reverse proxy to shield the application (presently a HTTP Basic authentication -yes we plan to upgrade to something stronger like SSL client certificate or smartcards-), and one at the application level
However we are currently running into a issue because the HTTP Basic Authorization header is conflicting with the Django Authorization header
The problem arises because the JWT auth from Django requires us to fill the "Authorization" header with the token while NGINX uses another type of authentication.
I'm looking for the best way to solve this problem and have the following questions :
is it possible to require Django to use an alternative HTTP header to carry its authentication token (instead of "Authorization")
or, conversely, is it possible to configure our nginx to use an alternative header for the HTTP Basic authentication (but it seems unlikely as it is done at the browser level) or to require the nginx to do the header translation : i.e. converting back and forth header before pushing them to the Django app.
or, even better, can we configure Django to stop using tokens and use the user authentified by nginx?
I'm looking for a solution that allows nginx to handle security and be responsible about it while adding another layer on top of it in Django what would be the best solution to try ?
Thanks

Redirecting API requests in Django Rest Framework

I have a two-layer backend architecture:
a "front" server, which serves web clients. This server's codebase is shared with a 3rd party developer
a "back" server, which holds top-secret-proprietary-kick-ass-algorithms, and has a single endpoint to do its calculation
When a client sends a request to a specific endpoint in the "front" server, the server should pass the request to the "back" server. The back server then crunches some numbers, and returns the result.
One way of achieving it is to use the requests library. A simpler way would be to have the "front" server simply redirect the request to the "back" server. I'm using DRF throughout both servers.
Is redirecting an ajax request possible using DRF?
You don't even need the DRF to add a redirection to urlconf. All you need to redirect is a simple rule:
urlconf = [
url("^secret-computation/$",
RedirectView.as_view(url=settings.BACKEND_SECRET_COMPUTATION_URL))),
url("^", include(your_drf_router.urls)),
]
Of course, you may extend this to a proper DRF view, register it with the DRF's router (instead of directly adding url to urlconf), etc etc - but there isn't much sense in doing so to just return a redirect response.
However, the code above would only work for GET requests. You may subclass HttpResponseRedirect to return HTTP 307 (replacing RedirectView with your own simple view class or function), and depending on your clients, things may or may not work. If your clients are web browsers and those may include IE9 (or worse) then 307 won't help.
So, unless your clients are known to be all well-behaving (and on non-hostile networks without any weird way-too-smart proxies - you'll never believe what kinds of insanity those may do to HTTP requests), I'd suggest to actually proxy the request.
Proxying can be done either in Django - write a GenericViewSet subclass that uses requests library - or by using something in front of it, e.g. nginx or Caddy (or any other HTTP server/load balancer that you know best).
For production purposes, as you probably have a fronting webserver, I suggest to use that. This would save implementation time and also a little bit of server resources, as your "front" Django project won't even have to handle the request and keep the worker busy as it waits for the response.
For development purposes, your options may vary. If you use bare runserver then a proxy view may be your best option. If you use e.g. Docker, you may just throw in an HTTP server container in front of your Django container.
For example, I currently have a two-project setup (legacy Django 1.6 project and newer Django 1.11 project, sharing the same database) and a Caddy server in front of those, routing on per-URL basis. With a simple 9-line Caddyfile things just work:
:80
tls off
log / stdout "{common}"
proxy /foo project1:8000 {
transparent
}
proxy / project2:8000 {
transparent
}
(This is a development-mode config.) If you can have something similar, then, I guess, that would be the simplest option.

Are cookies safe in a Heroku app on herokuapp.com?

I am developing an app, which I will deploy on Heroku. The app is only used within an iframe on another site, so I don't care about the domain name. I plan to deploy my app on example.herokuapp.com instead of using a custom domain on example.com.
My app uses cookies, and I want to be sure that others cannot manipulate my cookies to protect my app against session fixation and similar attacks. If attacker.herokuapp.com is able to set a cookie for herokuapp.com, browsers will not be able to protect me, since herokuapp.com is not a public suffix. See http://w2spconf.com/2011/papers/session-integrity.pdf for a detailed description of the issue.
My question is: When browsers can't protect my users, will Heroku do it by blocking cookies for herokuapp.com?
Just wanted to post an update for anyone who ran across this question as I did. I was working on a similar problem, except that I wanted to purposefully allow access to the same cookie from two different heroku apps.
"herokuapp.com" and "herokussl.com" are now on the Public Suffix List, so your cookies should be safe if they are set for one of those domains. I ended up having to use custom domains in order to share cookies across both apps.
Heroku also released an article on the topic: https://devcenter.heroku.com/articles/cookies-and-herokuapp-com
I just tried to add a cookie from my Heroku app with the response header Set-Cookie: name=value;Path=/;Domain=.herokuapp.com, and to my disappointment, I could see the header intact in my browser. So the Heroku infrastructure does not detect and remove this cross-app supercookie.
I see three possible ways to protect a Heroku app against cross-app supercookies:
Don't use cookies at all.
Use a custom domain.
Verify that each cookie was actually set by your app, and restrict it to the client's IP address by checking the X-Forwarded-For header.
My feature request to Heroku would be that they should filter HTTP responses that goes through their HTTP routing, such that applications hosted on their infrastructure cannot set cookies with Domain=herokuapp.com.
It seems to me that, as long as you set the cookie for example.herokuapp.com, then the cookie is safe from manipulation. The cookie will only be presented to the app running on example.herokuapp.com and to herokuapp.com (where no app runs).