I. State how detecting a target computer’s OS is very valuable to an attacker because once the OS is known, all of the vulnerabilities to which it is susceptible can easily be determined.
II. Stress that there are many tools that use networking protocols to determine a remote computer’s OS and adds additional opportunities to make them vulnerable to attacks.
III. Identify most OSs have a unique way of responding to ICMP requests. Provide additional to attention to XProbe as it is very reliable in finding matches and thus detecting the OSs of remote computers.
IV. Explain how system and network administrators should take note of this and plan to restrict the use of ICMPs through their organization’s firewalls and, when possible, within its internal networks.