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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2019.3446 Advisory (icsa-19-253-05) Siemens SIMATIC TDC CP51M1 11 September 2019 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Siemens SIMATIC TDC CP51M1 Publisher: ICS-CERT Operating System: Windows Impact/Access: Denial of Service -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2019-10937 Original Bulletin: https://www.us-cert.gov/ics/advisories/icsa-19-253-05 - --------------------------BEGIN INCLUDED TEXT-------------------- ICS Advisory (ICSA-19-253-05) Siemens SIMATIC TDC CP51M1 Original release date: September 10, 2019 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/ . 1. EXECUTIVE SUMMARY o CVSS v3 7.5 o ATTENTION: Exploitable remotely/low skill level to exploit o Vendor: Siemens o Equipment: SIMATIC TDC CP51M1 o Vulnerability: Improper Input Validation 2. RISK EVALUATION Successful exploitation of this vulnerability could create a denial-of-service condition within UDP communication. 3. TECHNICAL DETAILS 3.1 AFFECTED PRODUCTS The following versions of SIMATIC TDC CP51M1, a multiprocessor automation system, are affected: o SIMATIC TDC CP51M1: All versions prior to 1.1.7 3.2 VULNERABILITY OVERVIEW 3.2.1 IMPROPER INPUT VALIDATION CWE-20 An attacker sending a specially crafted UDP packet to the device may affect the UDP communication, causing a denial-of-service condition. CVE-2019-10937 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:N/S:U/ C:N/I:N/A:H ). 3.3 BACKGROUND o CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing o COUNTRIES/AREAS DEPLOYED: Worldwide o COMPANY HEADQUARTERS LOCATION: Germany 3.4 RESEARCHER Siemens reported this vulnerability to CISA. 4. MITIGATIONS Siemens recommends users update to Version 1.1.7 or later. Updates can be obtained at the following link: https://support.industry.siemens.com/cs/ww/en/view/27049282 Siemens has identified the following specific workarounds and mitigations that users may apply to reduce the risk: o Restrict network access to affected devices o Restrict UDP communication to affected devices o Do not use UDP communication in the user program if not needed o Apply cell protection concept and implement defense in depth As a general security measure, Siemens strongly recommends users protect network access to devices with appropriate mechanisms. In order to operate the devices in a protected IT environment, Siemens recommends users configure the environment according to Siemens' operational guidelines for industrial security (download: https://www.siemens.com/cert/ operational-guidelines-industrial-security ), and follow the recommendations in the product manuals. Additional information on industrial security by Siemens can be found at: https://www.siemens.com/industrialsecurity For more information, please see Siemens Security Advisory SSA-250618 at the following location: http://www.siemens.com/cert/advisories CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should: 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. - --------------------------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). 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