Schneider Electric Modicon M221 Information Management Errors, Permissions, Privileges, and Access Controls (CVE-2018-7792 CVE-2018-7791 CVE-2018-7790 )

# ICS Advisory (ICSA-18-240-01) ## Schneider Electric Modicon M221 Original release date: August 28, 2018 [Print Document](javascript:window.print\(\);) [Tweet](https://twitter.com/share?url=https%3A%2F%2Fus- cert.cisa.gov%2Fics%2Fadvisories%2FICSA-18-240-01) [Like Me](https://www.facebook.com/sharer.php?u=https%3A%2F%2Fus- cert.cisa.gov%2Fics%2Fadvisories%2FICSA-18-240-01) [Share](http://www.addthis.com/bookmark.php?url=https%3A%2F%2Fus- cert.cisa.gov%2Fics%2Fadvisories%2FICSA-18-240-01) ### 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 7.7** * **ATTENTION:** Exploitable remotely * **Vendor:** Schneider Electric * **Equipment:** Modicon M221 * **Vulnerabilities:** Information Management Errors, Permissions, Privileges, and Access Controls ## 2\. RISK EVALUATION Successful exploitation of these vulnerabilities may allow unauthorized users to replay authentication sequences, overwrite passwords, or decode passwords. ## 3\. TECHNICAL DETAILS ### 3.1 AFFECTED PRODUCTS Schneider Electric reports the vulnerabilities affect the following Modicon M221 products: * Modicon M221, all references, all versions prior to firmware v1.6.2.0 ### 3.2 VULNERABILITY OVERVIEW **3.2.1 [INFORMATION MANAGEMENT ERRORS CWE-199](https://cwe.mitre.org/data/definitions/199.html)** This vulnerability allows unauthorized users to replay authentication sequences. If an attacker exploits this vulnerability and connects to a Modicon M221, the attacker may upload the original program from the PLC. [CVE-2018-7790](http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2018-7790) has been assigned to this vulnerability. A CVSS v3 base score of 7.1 has been calculated; the CVSS vector string is (A[V:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L](https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L)). **3.2.2 [PERMISSIONS, PRIVILEGES, AND ACCESS CONTROLS CWE-264](https://cwe.mitre.org/data/definitions/264.html)** This vulnerability allows unauthorized users to overwrite the original password. If an attacker exploits this vulnerability and overwrites the password, the attacker may upload the original program from the PLC. [CVE-2018-7791](http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2018-7791) has been assigned to this vulnerability. A CVSS v3 base score of 7.7 has been assigned; the CVSS vector string is ([AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L](https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L)). **3.2.3 [PERMISSIONS, PRIVILEGES, AND ACCESS CONTROLS CWE-264](https://cwe.mitre.org/data/definitions/264.html)** This vulnerability allows unauthorized users to decode the password using a rainbow table. [CVE-2018-7792](http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2018-7792) has been assigned to this vulnerability. A CVSS v3 base score of 7.7 has been assigned; the CVSS vector string is ([AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L](https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L)). ### 3.3 BACKGROUND * **CRITICAL INFRASTRUCTURE SECTORS:** Commercial Facilities * **COUNTRIES/AREAS DEPLOYED:** Worldwide * **COMPANY HEADQUARTERS LOCATION:** France ### 3.4 RESEARCHER Irfan Ahmed, Hyunguk Yoo, Sushma Kalle, and Nehal Ameen of the University of New Orleans reported these vulnerabilities to NCCIC. ## 4\. MITIGATIONS A fix for these vulnerabilities is implemented in Modicon M221 Firmware v1.6.2.0, delivered within SoMachine Basic v1.6 SP2, which is available for download below, or by using Schneider Electric Software Update tool: <https://www.schneider- electric.com/en/download/document/SoMachineBasicV1.6SP2/> As a temporary mitigation, Modicon M221 users should take the following measures: * Set up a firewall blocking all remote/external access to Port 502. * Within the Modicon M221 application, users must disable all unused protocols, especially programming protocol, as described in section "Configuring Ethernet Network" of SoMachine Basic online help. This will prevent remote programming of the M221 PLC. Schneider Electric's security notice SEVD-2018-235-01 is available at the following location: <https://www.schneider-electric.com/en/download/document/SEVD-2018-235-01/> NCCIC 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](/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. NCCIC reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures. NCCIC also provides a section for [control systems security recommended practices](/ics/content/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](/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-CERT website](/ics/) in the Technical Information Paper, [ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies](/ics/tips/ICS-TIP-12-146-01B). Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to NCCIC for tracking and correlation against other incidents. No known public exploits specifically target these vulnerabilities. High skill level is needed to exploit.