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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2021.4036 Advisory (icsa-21-334-04) Johnson Controls CEM Systems AC2000 1 December 2021 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: CEM Systems AC2000 Publisher: ICS-CERT Operating System: Network Appliance Impact/Access: Root Compromise -- Existing Account Resolution: Mitigation CVE Names: CVE-2021-3156 Reference: ESB-2021.1815 ESB-2021.1330 Original Bulletin: https://us-cert.cisa.gov/ics/advisories/icsa-21-334-04 - --------------------------BEGIN INCLUDED TEXT-------------------- ICS Advisory (ICSA-21-334-04) Johnson Controls CEM Systems AC2000 Original release date: November 30, 2021 Legal Notice All information products included in https://us-cert.cisa.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://us-cert.cisa.gov/tlp/ . 1. EXECUTIVE SUMMARY o CVSS v3 7.8 o ATTENTION: Low attack complexity o Vendor: Controlled Electronic Management Systems, Ltd., a subsidiary of Johnson Controls, Inc. o Equipment: CEM Systems AC2000 o Vulnerability: Off-by-one Error 2. RISK EVALUATION Successful exploitation of this vulnerability could allow a local attacker to obtain "super user" access on the underlying Linux operating system. 3. TECHNICAL DETAILS 3.1 AFFECTED PRODUCTS The following versions of Controlled Electronic Management Systems Ltd. CEM Systems AC2000, an access control system, are affected: o CEM Systems AC2000: All versions prior to Version 10.6 3.2 VULNERABILITY OVERVIEW 3.2.1 OFF-BY-ONE ERROR CWE-193 The affected product has an off-by-one error vulnerability, which may allow an attacker to achieve "super user" access on the operating system. CVE-2021-3156 has been assigned to this vulnerability. A CVSS v3 base score of 7.8 has been assigned; the CVSS vector string is ( AV:L/AC:L/PR:L/UI:N/S:U/C:H/ I:H/A:H ). 3.3 BACKGROUND o CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing o COUNTRIES/AREAS DEPLOYED: Worldwide o COMPANY HEADQUARTERS LOCATION: Ireland 3.4 RESEARCHER Johnson Controls, Inc. reported this vulnerability to CISA. 4. MITIGATIONS Johnson Controls recommends users with AC2000 versions prior to 10.6 simply remove sudo. To do this, users may either contact a CEM support team or login to their Linux servers as root and type the following command: rpm -e sudo. Note: AC2000 v10.6 includes a fixed version of sudo. For more detailed mitigation instructions, please see Johnson Controls Product Security Advisory JCI-PSA-2021-20 v1 Aligning with CISA recommendations, Johnson Controls recommends taking steps to minimize risks to all building automation systems. CISA also recommends users take the following measures to protect themselves from social engineering attacks: o Do not click web links or open unsolicited attachments in email messages. o Refer to Recognizing and Avoiding Email Scams for more information on avoiding email scams. o Refer to Avoiding Social Engineering and Phishing Attacks for more information on social engineering attacks. 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.cisa.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.cisa.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 remotely. 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. 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