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crimecheck.py
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crimecheck.py
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#!/usr/bin/env python
"""
CrimeCheck - A Tool to check if the server is vulnerable to Compression Based Attacks(BREACH/CRIME)
usage: PROGRAM [options] <...>
-v Verbose logging
-l log_file Log output to logfile
-s Server URL
-p Pcap File (Live Capture is not supported currently)
Copyright (C) 2013 Achin K, mail: achinkul@gmail.com
Thanks to Paul Querna for the amazing parser
"""
import urllib2
import logging, getopt
import os
import sys
import socket
p = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'third_party', 'dpkt')
if p not in sys.path:
sys.path.insert(0, p)
import dpkt
from collections import defaultdict
capture=""
def sendRequest(serverAddr):
req = urllib2.Request("https://"+serverAddr)
req.add_header('Accept-Encoding', 'gzip,deflate')
resp = urllib2.urlopen(req)
content = resp.read()
logger.debug("%s", resp.info())
return resp.info().getheader('Content-Encoding')
def checkIfVulnerable(respCode,serverAddr):
if respCode:
logger.info("HTTP Compression for Server %s is ENABLED ",serverAddr)
else:
logger.info("HTTP Compression for Server %s is DISABLED",serverAddr)
def pcap_reader(fp):
return dpkt.pcap.Reader(fp)
def as_percent(a, b):
if a == 0:
return "0%"
if a > b:
assert('invalid percentage')
val = float(a) / float(b)
return "%.2f%%" % (val * 100)
TLS_HANDSHAKE = 22
def gather_statistics(cap,serverAddr):
counters = defaultdict(int)
known_extensions = set()
count_extensions = set()
pkt_count = 0
for ts, buf in cap:
pkt_count += 1
eth = dpkt.ethernet.Ethernet(buf)
#print 'pkt: %d' % (pkt_count)
if not isinstance(eth.data, dpkt.ip.IP):
continue
ip = eth.data
if not isinstance(ip.data, dpkt.tcp.TCP):
continue
# TODO: consider doing TCP streams, so multi-packet things can be parsed right... "meh"
tcp = ip.data
if tcp.dport != 443 and tcp.sport != 443:
continue
if socket.gethostbyname(serverAddr) != socket.inet_ntoa(ip.src):
continue
if len(tcp.data) <= 0:
continue
# we only care about handshakes for now...
if ord(tcp.data[0]) != TLS_HANDSHAKE:
continue
records = []
try:
records, bytes_used = dpkt.ssl.TLSMultiFactory(tcp.data)
except dpkt.ssl.SSL3Exception, e:
# TODO: debug these
continue
except dpkt.dpkt.NeedData, e:
# TODO: meeeeh
continue
if len(records) <= 0:
continue
for record in records:
logger.debug("%s", record)
# TLS handshake only
if record.type != 22:
continue
if len(record.data) == 0:
continue
# Client Hello only
if ord(record.data[0]) != 2:
continue
counters['Handshake_hellos_total'] += 1
if counters['Handshake_hellos_total'] == 1:
try:
handshake = dpkt.ssl.TLSHandshake(record.data)
except dpkt.dpkt.NeedData, e:
# TODO: shouldn't happen in practice for handshakes... but could. meh.
continue
ch = handshake.data
if ch.version == dpkt.ssl.SSL3_V:
counters['SSLv3_clients'] += 1
elif ch.version == dpkt.ssl.TLS1_V:
counters['TLSv1_clients'] += 1
elif ch.version == dpkt.ssl.TLS11_V:
counters['TLSv1.1_clients'] += 1
elif ch.version == dpkt.ssl.TLS12_V:
counters['TLSv1.2_clients'] += 1
if len(ch.session_id) > 0:
counters['session_id_sent'] += 1
if ch.compression != 0:
counters['TLSCompression'] += 1
if counters['TLSCompression'] > 0:
logger.info("The TLS Compression for server %s is ENABLED", serverAddr)
break
else:
logger.info("The TLS Compression for server %s is DISABLED", serverAddr)
break
if counters['Handshake_hellos_total'] == 0:
logger.info("The PCAP file doesn't contain any SSL Handshake Packets corresponding to %s ", serverAddr)
if __name__ == '__main__':
__usage__ = __doc__.replace("PROGRAM", os.path.basename(sys.argv[0]))
logger = logging.getLogger()
logger.setLevel(logging.INFO)
fileHandler = None
serverAddr = ""
def die_usage(msg=""):
sys.stderr.write("%s%s\n" % (__usage__, msg))
sys.exit(1)
try:
opts, args = getopt.getopt(sys.argv[1:], "hvl:s:p:", ["help", "verbose", "log-file", "server-url"])
except getopt.GetoptError, e:
die_usage(str(e))
for o, a in opts:
if o in ("-h","--help"): die_usage()
if o in ("-v", "--verbose"): logger.setLevel(logging.DEBUG)
if o in ("-l", "--log-file"): fileHandler = logging.FileHandler(a)
if o in ("-s", "--server-url"):
serverAddr = str(a)
pcap = None
if o in ("-p", "--pcap-file"):
if a:
pcap = str(a)
else:
logger.info("Please enter a valid pcap file")
handler = logging.StreamHandler(sys.stdout)
formatter = logging.Formatter('%(asctime)s %(levelname)s %(message)s')
handler.setFormatter(formatter)
logger.addHandler(handler)
if (fileHandler is not None):
fileHandler.setFormatter(formatter)
logger.addHandler(fileHandler)
if serverAddr == "":
die_usage("\nPlease Enter Server Address")
try:
logger.info("Ready. Sending Request to server %s", serverAddr)
respCode = sendRequest(serverAddr)
checkIfVulnerable(respCode,serverAddr)
logger.info("Checking TLS Compression for %s", serverAddr)
if pcap:
fp = open(pcap,'rb')
capture = pcap_reader(fp)
stats = gather_statistics(capture, serverAddr)
else:
logger.info("To check for TLS Compression, Please provide a PCAP file")
except Exception as e :
logger.info("Error - %s",e)