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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2020.3077.2 Advisory (icsa-20-252-02) Siemens SIMATIC S7-300 and S7-400 CPUs 14 October 2020 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Siemens SIMATIC S7-300 S7-400 CPUs Publisher: US-CERT Operating System: Network Appliance Impact/Access: Access Confidential Data -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2020-15791 Original Bulletin: https://us-cert.cisa.gov/ics/advisories/icsa-20-252-02 Revision History: October 14 2020: Release of minor update A September 9 2020: Initial Release - --------------------------BEGIN INCLUDED TEXT-------------------- ICS Advisory (ICSA-20-252-02) Siemens SIMATIC S7-300 and S7-400 CPUs (Update A) Original release date: October 13, 2020 Legal Notice All information products included in https://us-cert.gov/ics 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 https://www.us-cert.gov/tlp/ . 1. EXECUTIVE SUMMARY o CVSS v3 5.3 o ATTENTION: Low skill level to exploit o Vendor: Siemens o Equipment: SIMATIC S7-300 and S7-400 CPUs o Vulnerability: Insufficiently Protected Credentials 2. UPDATE INFORMATION This updated advisory is a follow-up to the original advisory titled ICSA-20-252-02 Siemens SIMATIC S7-300 and S7-400 CPUs that was published September 8, 2020, to the ICS webpage on us-cert.gov. 3. RISK EVALUATION Successful exploitation of this vulnerability could result in credential disclosure. 4. TECHNICAL DETAILS 4.1 AFFECTED PRODUCTS Siemens reports the vulnerability affects the following versions of SIMATIC S7-300 and S7-400 CPU families: o SIMATIC S7-300 CPU family (incl. related ET200 CPUs and SIPLUS variants): All versions o SIMATIC S7-400 CPU family (incl. SIPLUS variants): All versions - --------- Begin Update A Part 1 of 1 --------- o SIMATIC WinAC RTX (F) 2010: All versions o SINUMERIK 840D sl: All versions - --------- End Update A Part 1 of 1 --------- 4.2 VULNERABILITY OVERVIEW 4.2.1 INSUFFICIENTLY PROTECTED CREDENTIALS CWE-522 The authentication protocol between a client and a PLC via Port 102/TCP (ISO-TSAP) insufficiently protects the transmitted password. This could allow an attacker that is able to intercept the network traffic to obtain valid PLC credentials. CVE-2020-15791 has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been calculated; the CVSS vector string is ( AV:A/AC:H/PR:N/UI:N/S:U/ C:H/I:N/A:N ). 4.3 BACKGROUND o CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing o COUNTRIES/AREAS DEPLOYED: Worldwide o COMPANY HEADQUARTERS LOCATION: Germany 4.4 RESEARCHER Hyunguk Yoo from University of New Orleans and Irfan Ahmed and Adeen Ayub from Virginia Commonwealth University reported this vulnerability to Siemens. 5. MITIGATIONS Siemens has identified the following specific workarounds and mitigations users can apply to reduce the risk: o Apply defense-in-depth concepts . o Apply cell protection concepts . o For SIMATIC S7-CPU 410 CPUs: Activate field interface security in PCS 7 v9.0, and use a CP443-1 Adv. to communicate with ES/OS As a general security measure, Siemens strongly recommends protecting network access to devices with appropriate mechanisms. In order to operate the devices in a protected IT environment, Siemens recommends configuring the environment according to Siemens' operational guidelines for Industrial Security , and following the recommendations in the product manuals. Follow this link for additional information on Industrial Security by Siemens . For more information on this vulnerability and the associated mitigations, please see Siemens security advisory SSA-381684 CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should: o Minimize network exposure for all control system devices and/or systems, and ensure that they are not accessible from the Internet . o Locate control system networks and remote devices behind firewalls, and isolate them from the business network. o 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. CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures. CISA also provides a section for control systems security recommended practices on the ICS webpage on us-cert.gov . 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 on the ICS webpage on us-cert.gov in the Technical Information Paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies . Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to CISA for tracking and correlation against other incidents. No known public exploits specifically target this vulnerability. This vulnerability is not exploitable from adjacent networks. For any questions related to this report, please contact the CISA at: Email: CISAservicedesk@cisa.dhs.gov Toll Free: 1-888-282-0870 CISA continuously strives to improve its products and services. You can help by choosing one of the links below to provide feedback about this product. - --------------------------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: https://www.auscert.org.au/bulletins/ =========================================================================== 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 iQIVAwUBX4Z6KONLKJtyKPYoAQi4CQ/9EAU460RvuJyXjx9ESSNY/HbSbQtBlEV/ Y7RhvxDP0+7oZs2ukqIIOM65itcHeon5XQ24YPykBIux1mZeQDCdfv1nIIuj7ZSv kbvnVWM6fq/fLKxtjgJrl6l+ygysPkgu145/etoDWQKtRxHAgbueqEpBi/2B1sjw ubI8v0r0jwpQaCbMcl6pWrrBwZyLmcgWMlFmakco0Q+1yJpoCb62mGktOvkLTzhY dIk8+bxBgTSlLAoUP6SKvw4LmUcaWwmdqMmUNpLGhJ1G8dIDCeC7bTKP/qYE425L CZ+gDv/atdpeX8ak0ev9+uEm+Vsq5QWU773326zTINoxmENwFOF3moTo0T/9XwCr dH3ohKAO/KUu9SC3yI30Fa8gX040JOO3c8w2XgxTdfg3VV985HOEX/n6HH1XoqGl JlvZ7JrlHb914/pZgxzjXuHMb/ThxWoD+bdcbdjOprmpNiIcglKn+Sw4sofuswn+ RB1SDTWVIR3V5GOxRdhhChFECdWo/KwT7julgHw5wMb8qIKc6fFgpH75jdkn/LNG oQVtKteFU9TAxHTL3doH/b9/ySIuaE81fieCLiSmua9VCUK6Mg5lCyxV3Vd3DjNN k/+tTA/UqjbkfFV8aGLxgLE1ufBiiik7l44VqAmMtie0tR6sfvFkGg7dSTfv2Uv8 A3LYOB4Gn8A= =W3p7 -----END PGP SIGNATURE-----