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# -*- encoding: utf-8 -*-
# :authors: Arturo Filastò
# :licence: see LICENSE
import random
import json
import yaml
from twisted.python import usage
from ooni.utils import log, net, randomStr
from ooni.templates import httpt
from ooni.common.txextra import TrueHeaders
def random_capitalization(string):
output = ""
original_string = string
string = string.swapcase()
for i in range(len(string)):
if random.randint(0, 1):
output += string[i].swapcase()
output += string[i]
if original_string == output:
return random_capitalization(output)
return output
class UsageOptions(usage.Options):
optParameters = [
['backend', 'b', None,
'URL of the backend to use for sending the requests.'],
['headers', 'h', None,
'Specify a yaml formatted file from which to read '
'the request headers to send.']
class HTTPHeaderFieldManipulation(httpt.HTTPTest):
It performes HTTP requests with request headers that vary capitalization
towards a backend. If the headers reported by the server differ from
the ones we sent, then we have detected tampering.
name = "HTTP Header Field Manipulation"
description = "Checks if the HTTP request the server " \
"sees is the same as the one that the client has created."
author = "Arturo Filastò"
version = "0.2.0"
randomizeUA = False
usageOptions = UsageOptions
requiredTestHelpers = {'backend': 'http-return-json-headers'}
requiredOptions = ['backend']
requiresTor = False
requiresRoot = False
def setUp(self):
super(HTTPHeaderFieldManipulation, self).setUp()
self.url = self.localOptions['backend']
def get_headers(self):
headers = {}
if self.localOptions['headers']:
f = open(self.localOptions['headers'])
except IOError:
raise Exception("Specified input file does not exist")
content = ''.join(f.readlines())
headers = yaml.safe_load(content)
return headers
# XXX generate these from a random choice taken from
headers = {
"User-Agent": [
"Accept": ["text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"],
"Accept-Encoding": ["gzip,deflate,sdch"],
"Accept-Language": ["en-US,en;q=0.8"],
"Accept-Charset": ["ISO-8859-1,utf-8;q=0.7,*;q=0.3"],
"Host": [
randomStr(15) +
return headers
def get_random_caps_headers(self):
headers = {}
normal_headers = self.get_headers()
for k, v in normal_headers.items():
new_key = random_capitalization(k)
headers[new_key] = v
return headers
def processResponseBody(self, data):
def check_for_tampering(self, data):
Here we do checks to verify if the request we made has been tampered
with. We have 3 categories of tampering:
* **total** when the response is not a json object and therefore we were not
able to reach the ooniprobe test backend
* **request_line_capitalization** when the HTTP Request line (e.x. GET /
HTTP/1.1) does not match the capitalization we set.
* **header_field_number** when the number of headers we sent does not match
with the ones the backend received
* **header_name_capitalization** when the header field names do not match
those that we sent.
* **header_field_value** when the header field value does not match with the
one we transmitted.
log.msg("Checking for tampering on %s" % self.url)['tampering'] = {
'total': False,
'request_line_capitalization': False,
'header_name_capitalization': False,
'header_field_value': False,
'header_field_number': False
response = json.loads(data)
except ValueError:['tampering']['total'] = True
request_request_line = "%s / HTTP/1.1" % self.request_method
response_request_line = response['request_line']
response_headers_dict = response['headers_dict']
except KeyError:['tampering']['total'] = True
if request_request_line != response_request_line:['tampering']['request_line_capitalization'] = True
request_headers = TrueHeaders(self.request_headers)
diff = request_headers.getDiff(TrueHeaders(response_headers_dict),
if diff:['tampering']['header_field_name'] = True
else:['tampering']['header_field_name'] = False['tampering']['header_name_diff'] = list(diff)
log.msg(" total: %(total)s" %['tampering'])
" request_line_capitalization: %(request_line_capitalization)s" %['tampering'])
" header_name_capitalization: %(header_name_capitalization)s" %['tampering'])
" header_field_value: %(header_field_value)s" %['tampering'])
" header_field_number: %(header_field_number)s" %['tampering'])
def test_get_random_capitalization(self):
self.request_method = random_capitalization("GET")
self.request_headers = self.get_random_caps_headers()
return self.doRequest(self.url, self.request_method,