Siemens SIMATIC S7-300 and S7-400 CPUs (CVE-2020-15791)

# ICS Advisory (ICSA-20-252-02) ## Siemens SIMATIC S7-300 and S7-400 CPUs (Update A) Original release date: October 13, 2020 [Print Document](javascript:window.print\(\);) [Tweet](https://twitter.com/share?url=https%3A%2F%2Fus- cert.cisa.gov%2Fics%2Fadvisories%2Ficsa-20-252-02) [Like Me](https://www.facebook.com/sharer.php?u=https%3A%2F%2Fus- cert.cisa.gov%2Fics%2Fadvisories%2Ficsa-20-252-02) [Share](http://www.addthis.com/bookmark.php?url=https%3A%2F%2Fus- cert.cisa.gov%2Fics%2Fadvisories%2Ficsa-20-252-02) ### Legal Notice All information products included in [https://us-cert.gov/ics](/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/](/tlp/). * * * ## 1\. EXECUTIVE SUMMARY * **CVSS v3 5.3** * **ATTENTION:** Low skill level to exploit * **Vendor:** Siemens * **Equipment:** SIMATIC S7-300 and S7-400 CPUs * **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: * SIMATIC S7-300 CPU family (incl. related ET200 CPUs and SIPLUS variants): All versions * SIMATIC S7-400 CPU family (incl. SIPLUS variants): All versions **\--------- Begin Update A Part 1 of 1 --------- ** * SIMATIC WinAC RTX (F) 2010: All versions * SINUMERIK 840D sl: All versions **\--------- End Update A Part 1 of 1 --------- ** ### 4.2 VULNERABILITY OVERVIEW #### 4.2.1 [INSUFFICIENTLY PROTECTED CREDENTIALS CWE-522](https://cwe.mitre.org/data/definitions/522.html) 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](http://web.nvd.nist.gov/view/vuln/detail?vulnId=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](https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N/E:P/RL:U/RC:C)). ### 4.3 BACKGROUND * **CRITICAL INFRASTRUCTURE SECTORS:** Critical Manufacturing * **COUNTRIES/AREAS DEPLOYED:** Worldwide * **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: * Apply [defense-in-depth concepts](https://www.siemens.com/industrialsecurity). * Apply [cell protection concepts](https://www.siemens.com/cert/operational-guidelines-industrialsecurity). * 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](https://www.siemens.com/cert/operational-guidelines-industrial- security), and following the recommendations in the product manuals. Follow this link for additional information on [Industrial Security by Siemens](https://www.siemens.com/Industrialsecurity). For more information on this vulnerability and the associated mitigations, please see Siemens security advisory [SSA-381684](https://new.siemens.com/global/en/products/services/cert.html#SecurityPublications) CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should: * Minimize network exposure for all control system devices and/or systems, and ensure that they are [not accessible from the Internet](https://www.us-cert.gov/ics/alerts/ICS-ALERT-10-301-01). * 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. 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](https://www.us-cert.gov/ics/recommended-practices) on the ICS webpage on [us-cert.gov](https://www.us-cert.gov/ics). Several recommended practices are available for reading and download, including [Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies](https://www.us- cert.gov/sites/default/files/recommended_practices/NCCIC_ICS- CERT_Defense_in_Depth_2016_S508C.pdf). Additional mitigation guidance and recommended practices are publicly available on the [ICS webpage on us-cert.gov](https://www.us-cert.gov/ics) in the Technical Information Paper, [ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies](https://www.us-cert.gov/ics/tips/ICS- TIP-12-146-01B). 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. ## Contact Information For any questions related to this report, please contact the CISA at: Email: [CISAservicedesk@cisa.dhs.gov](mailto:cisaservicedesk@cisa.dhs.gov) Toll Free: 1-888-282-0870 For industrial control systems cybersecurity information: [https://www.us- cert.gov/ics](/ics) or incident reporting: [https://www.us-cert.gov/report](/report) 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. This product is provided subject to this [Notification](/privacy/notification) and this [Privacy & Use](https://www.dhs.gov/privacy-policy) policy. 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