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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2017.0945 Advisory (ICSA-17-101-01) Schneider Electric Modicon Modbus Protocol 12 April 2017 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Modicon Modbus Protocol Publisher: Schneider Electric Operating System: Network Appliance Impact/Access: Provide Misleading Information -- Remote with User Interaction Resolution: Mitigation CVE Names: CVE-2017-6034 CVE-2017-6032 Original Bulletin: http://ics-cert.us-cert.gov/advisories/ICSA-17-101-01 - --------------------------BEGIN INCLUDED TEXT-------------------- Advisory (ICSA-17-101-01) Schneider Electric Modicon Modbus Protocol Original release date: April 11, 2017 Legal Notice All information products included in http://ics-cert.us-cert.gov are provided "as is" for informational purposes only. The Department of Homeland Security (DHS) does not provide any warranties of any kind regarding any information contained within. DHS does not endorse any commercial product or service, referenced in this product or otherwise. Further dissemination of this product is governed by the Traffic Light Protocol (TLP) marking in the header. For more information about TLP, see http://www.us-cert.gov/tlp/. CVSS v3 10.0 ATTENTION: Remotely exploitable/low skill level to exploit. Vendor: Schneider Electric Equipment: Modicon Modbus Protocol Vulnerabilities: Authentication Bypass by Capture-Replay, Violation of Secure Design Principles AFFECTED PRODUCTS The following versions of Modicon Modbus protocol, which can be used with the Modicon family of programmable logic controllers (PLCs), are affected: Modicon Modbus protocol, all versions. IMPACT Successful exploitation of these vulnerabilities may allow an unauthorized remote attacker to capture and replay sensitive commands to PLCs on a network using the Modicon Modbus protocol. MITIGATION Schneider Electric has reported that they have introduced compensating controls to limit the exploitability of the identified vulnerabilities in many of the PLCs in the Modicon family; however, Schneider Electric recommends that users apply security measures to improve resiliency. Schneider Electric's Momentum M1E controllers (all versions of model 171CBU98090 and all versions of model 171CBU98091) do not have built-in compensating controls to limit the exploitability of the identified vulnerabilities and Schneider Electric instructs users to take the following defensive measures: Protect access to M1E controllers by a firewall blocking all remote/external access to Port 502. Schneider Electric reports that Modicon M340, M580, Premium and Quantum users should take one or more of the following defensive measures: Enable protection based on an authentication to connect to PLC. This method relies on a feature named Application Password. Once enabled, password-based authentication is required whenever a user connects to change their application program; Enable protection relying on an input (M340, Premium, Quantum) or a key switch in the front panel (Quantum) to reject remote connection or run/stop commands; and Enable the "Access Control List protection," where users are able to configure the restricted IP addresses that are pre-authorized to control the PLC. For additional information, Schneider Electric has released a Cybersecurity Notification, which is available at the following location: http://www.schneider-electric.com/en/download/document/SEVD-2017-065-01/ (link is external) NCCIC/ICS-CERT recommends that users take defensive measures to minimize the risk of exploitation of these vulnerabilities. Specifically, users should: Minimize network exposure for all control system devices and/or systems, and ensure that they are not accessible from the Internet. Locate control system networks and remote devices behind firewalls, and isolate them from the business network. When remote access is required, use secure methods, such as Virtual Private Networks (VPNs), recognizing that VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize that VPN is only as secure as the connected devices. ICS-CERT reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures. ICS-CERT also provides a section for control systems security recommended practices on the ICS-CERT web page. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies. Additional mitigation guidance and recommended practices are publicly available in the ICS-CERT Technical Information Paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies, that is available for download from the ICS-CERT web site. Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to ICS-CERT for tracking and correlation against other incidents. VULNERABILITY OVERVIEW AUTHENTICATION BYPASS BY CAPTURE-REPLAY CWE-294 Sensitive information is transmitted in cleartext in the Modicon Modbus protocol, which may allow an attacker to replay the following commands: run, stop, upload, and download. CVE-2017-6034 has been assigned to this vulnerability. A CVSS v3 base score of 10.0 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H) VIOLATION OF SECURE DESIGN PRINCIPLES CWE-657 The Modicon Modbus protocol has a session-related weakness making it susceptible to brute-force attacks. CVE-2017-6032 has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N). RESEARCHER Eran Goldstein of CRITIFENCE reported the identified vulnerabilities. BACKGROUND Critical Infrastructure Sectors: Critical Manufacturing, Dams, Defense Industrial Base, Energy, Food and Agriculture, Government Facilities, Nuclear Reactors, Materials, and Waste, Transportation Systems, and Water and Wastewater Systems Countries/Areas Deployed: Worldwide Company Headquarters Location: Paris, France - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/render.html?cid=1980 =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQIVAwUBWO27zIx+lLeg9Ub1AQiEuQ/+J0ecewVqsLEH9qkWgz5sBeJFVz63AHCz TYFjbngz2CzJ/uKua8gJDcOHW9JU6t2tFooCiq7DH3LuyDXRlPiWsZlSPogB6DXk 3Oi1miSQX64REfBt4qcA+DD2lbWp2y+iGcZtO/eAsoV6orqIVGQR4RJP2O6ZXs0W PDm7no5e4KO+dvTuR5m+r/5mx4LURKpfmgrP42vM/uRVFR8myA1HS6xM6N83smCD amOc6retHhcS9s7PAgW1ntY1cUJNssKgS5EYse6vpT0kBQtTXd+ew/ynmXEqu1EZ 5NAtQSnRT41f8Mu1gkuWPQbraa7vWwTr+L5dR1ZI5qrKEzDoyM8r2agU3gO5e2XP /yP6jfNAqoYqVV0P25/N/a7eq7MaIheUfQnslrSC0kIS/lxExxsAczL5C369cswG OHH3mEC/4He28fJagekCdHxwj+C1jnilxfbAl1skS08rb0EI0PvINLwXrGpCrhWd WyUny90E+9DidskaO5vXo/z2IB9m8QOoSGeMJA+fV7gUV5QwZem41rmYZ7GmS92R LXRyVAMVf/8inxKjWO7EcTJxqpDH62mgwoukCT005xtba/rLF8b0vAjhvtZ6MI9w XtYa3n3GwhiTepl3dTQkykgfnoAaGtbO887HWfD3T4/CHaM9diJiYDQcMONjpkFJ 7GOBOcGFWA8= =Icis -----END PGP SIGNATURE-----