Which filter to locate unusual ICMP request an Analyst can use in order to detect...

In the context of network security, ICMP fingerprinting is a technique used to determine the operating system of a target machine by analyzing its responses to ICMP requests. The correct filter to detect unusual ICMP requests that could be indicative of ICMP probes from an attacker is option C. This filter looks for ICMP echo requests (type 8) that do not have a corresponding echo reply (code 0). Since the code for an echo request is 0, the filter (!(icmp.code==8)) is used to exclude other ICMP messages with different codes.

References: The use of Wireshark filters to identify specific types of ICMP traffic is a common practice in network analysis. The Certified Network Defender (CND) course material covers various network monitoring tools and techniques, including the analysis of ICMP traffic for security purposes1. Additionally, resources like Wireshark documentation and network security forums provide practical examples of filters used to detect ICMP fingerprinting attempts23.