- Regularly apply available security patches and updates - Implement strong network segmentation to isolate legacy systems from critical infrastructure - Use firewalls and intrusion detection systems (IDS) to monitor and protect legacy OS - Limit user access and enforce strict authentication policies (e.g., multi-factor authentication) - Disable unnecessary services and ports to reduce the attack surface - Implement application whitelisting to control executable programs - Regularly back up data and create a disaster recovery plan - Monitor logs for suspicious activities and automate alerts

Securing legacy operating systems involves: 1. Regular patch management, including third-party solutions. 2. Network segmentation to isolate legacy systems. 3. Strict access controls and multi-factor authentication. 4. Frequent security audits. 5. Updated antivirus and intrusion detection. Develop a plan for gradual system replacement.