To search for additional downloads of a malicious file by other hosts, the file hash value is needed. The hash value provides a unique identifier for each specific file version, enabling cybersecurity professionals to track down identical files across networks. References := Cisco Certified CyberOps Associate Overview

To isolate the suspicious host that is performing intensive network scanning, the analyst should collect the traffic by most active source IP. This will help to identify the IP address of the host that is generating the most traffic and sending the most packets or bytes. The analyst can then apply filters or queries to analyze the traffic from that source IP and determine the nature and scope of the scanning activity. References := Understanding Cisco Cybersecurity Operations Fundamentals (CBROPS) - Cisco, page 72; [Cisco CyberOps Associate CBROPS 200-201 Official Cert Guide], page 468

Enabling the "Allow subdissector to reassemble TCP streams" feature in Wireshark allows the tool to reassemble TCP segments into a contiguous sequence, which can be used by higher-level protocols to reconstruct a full message, such as an HTTP request or response. This is particularly useful for extracting files or data transmitted over TCP that are spread across multiple packets1.
References := The explanation is based on the Wireshark documentation, which details how the reassembly feature works and its use in analyzing TCP streams