Windows operating system includes a built-in antivirus software called Windows Defender. It provides real-time protection against various types of malware, including viruses, spyware, and ransomware. Windows Defender is automatically enabled and updated on Windows computers to help keep the system secure. Note: macOS and Linux operating systems have their own security features, but they do not include Windows Defender. macOS has a built-in security tool called XProtect, which provides some protection against malware, and Linux offers various security features such as SELinux (Security-Enhanced Linux) and AppArmor.

Defense in depth is a cybersecurity strategy that involves implementing multiple layers of security controls to protect against various types of threats. This approach provides greater resilience and mitigates potential vulnerabilities. By implementing multiple layers, even if one control fails, others can still safeguard the system.

An Access Control List (ACL) is a list of rules that determines which network traffic is allowed and which is denied. It is used to filter network traffic based on criteria such as source/destination IP address, port numbers, and protocols. By implementing an ACL, organizations can control access to their networks, prevent unauthorized access, and enforce security policies.

Security events that should be escalated typically include critical vulnerabilities that could lead to potential breaches or unauthorized access. In this case, the system administrator detecting a critical vulnerability on a server requires immediate attention and escalation to ensure prompt action can be taken to mitigate the risk.

Port scanning is a technique used to identify open ports and services running on a target system. By scanning the ports, a cybersecurity professional can gather valuable information about the target, such as the services and protocols in use, which can help in identifying potential vulnerabilities and securing the system.