OnSystem Defender by OnSystem Logic is an application hardening and control solution for endpoints. It provides protection against malware, ransomware, and application vulnerabilities, including zero-day attacks, backdoors, unpatched and unpatchable issues, and software supply chain threats. OnSystem Defender uses real-time application memory control and application control policies to monitor and manage application behavior based on known 'good' actions. It implements multi-layered filtering for real-time protection and prevents unauthorized application actions.