Original Article Summary

View CSAF 1. EXECUTIVE SUMMARY CVSS v4 9.3 ATTENTION: Exploitable remotely/low attack complexity Vendor: Emerson Equipment: Appleton UPSMON-PRO Vulnerability: Stack-based Buffer Overflow 2. RISK EVALUATION Successful exploitation of this vulnerability could allow remote attackers to execute arbitrary code on affected installations of Appleton UPSMON-PRO. 3. TECHNICAL DETAILS 3.1 AFFECTED PRODUCTS The following Emerson products are affected: Appleton UPSMON-PRO: Versions 2.6 and prior 3.2 VULNERABILITY OVERVIEW 3.2.1 STACK-BASED BUFFER OVERFLOW CWE-121 A crafted UDP packet sent to the default UDP port 2601 can cause an overflow of the buffer stack, overwriting critical memory locations. This could allow unauthorized individuals to execute arbitrary code with SYSTEM privileges if the UPSMONProService service communication is not properly validated. CVE-2024-3871 has been assigned to this vulnerability. A CVSS v3.1 base score of 9.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H). A CVSS v4 score has also been calculated for CVE-2024-3871. A base score of 9.3 has been calculated; the CVSS vector string is (AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N). 3.3 BACKGROUND CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing, Healthcare and Public Health COUNTRIES/AREAS DEPLOYED: Worldwide COMPANY HEADQUARTERS LOCATION: United States 3.4 RESEARCHER kimiya working with Trend Micro's Zero Day Initiative reported this vulnerability to CISA. 4. MITIGATIONS According to Emerson, Appleton UPSMON-PRO is End of Life and unsupported. Any users still using the product are recommended to replace the product or apply the following mitigations based on your company policies and Cybersecurity Operational recommendations. Recommended Actions if not replaced: Block UDP port 2601 at firewall level for all UPSMON-PRO installations Isolate UPS monitoring networks from general corporate networks Implement network-level packet filtering to reject oversized UDP packets to port 2601 Monitor for UPSMONProSer.exe service crashes as potential indicators of exploitation attempts Long-term Strategy Recommendation: Replace UPSMON-PRO with actively supported UPS monitoring solution Implement defense-in-depth strategies for critical power infrastructure monitoring CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability, such as: Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the internet. Locate control system networks and remote devices behind firewalls and isolating them from business networks. When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize 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 cisa.gov/ics. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies. CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets. Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies. Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents. No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time. 5. UPDATE HISTORY November 20, 2025: Initial Publication