Django's SuspiciousOperation Invalid HTTP_HOST header

Question

After upgrading to Django 1.5, I started getting errors like this:

Traceback (most recent call last):

File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py", line 92, in get_response
response = middleware_method(request)

File "/usr/local/lib/python2.7/dist-packages/django/middleware/common.py", line 57, in process_request
host = request.get_host()

File "/usr/local/lib/python2.7/dist-packages/django/http/request.py", line 72, in get_host
"Invalid HTTP_HOST header (you may need to set ALLOWED_HOSTS): %s" % host)

SuspiciousOperation: Invalid HTTP_HOST header (you may need to set ALLOWED_HOSTS): www.google.com

<WSGIRequest
path:/,
GET:<QueryDict: {}>,
POST:<QueryDict: {}>,
COOKIES:{},
META:{'CONTENT_LENGTH': '',
'CONTENT_TYPE': '',
'DOCUMENT_ROOT': '/etc/nginx/html',
'HTTP_ACCEPT': 'text/html',
'HTTP_HOST': 'www.google.com',
'HTTP_PROXY_CONNECTION': 'close',
'HTTP_USER_AGENT': 'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)',
'PATH_INFO': u'/',
'QUERY_STRING': '',
'REMOTE_ADDR': '210.245.91.104',
'REMOTE_PORT': '49347',
'REQUEST_METHOD': 'GET',
'REQUEST_URI': '/',
u'SCRIPT_NAME': u'',
'SERVER_NAME': 'www.derekkwok.net',
'SERVER_PORT': '80',
'SERVER_PROTOCOL': 'HTTP/1.0',
'uwsgi.node': 'derekkwok',
'uwsgi.version': '1.4.4',
'wsgi.errors': <open file 'wsgi_errors', mode 'w' at 0xb6d99c28>,
'wsgi.file_wrapper': <built-in function uwsgi_sendfile>,
'wsgi.input': <uwsgi._Input object at 0x953e698>,
'wsgi.multiprocess': True,
'wsgi.multithread': False,
'wsgi.run_once': False,
'wsgi.url_scheme': 'http',
'wsgi.version': (1, 0)}>

I've set ALLOWED_HOSTS = ['.derekkwok.net'] in my settings.py file.

What is going on here? It someone pretending to be Google and accessing my site? Or is it a benign case of someone setting their HTTP_HOST header incorrectly?

Answer 1

If you're using Nginx to forward requests to Django running on Gunicorn/Apache/uWSGI, you can use the following to block bad requests. Thanks to @PaulM for the suggestion.

upstream app_server {
    server unix:/tmp/gunicorn_mydomain.com.sock fail_timeout=0;
}

server {

    ...

    ## Deny illegal Host headers
    if ($host !~* ^(mydomain.com|www.mydomain.com)$ ) {
        return 444;
    }

    location  / {
        proxy_pass               http://app_server;
        ...
    }

}