Section: Security Concepts

NetFlow is a network protocol developed by Cisco for collecting IP traffic information and monitoring network flow. It provides valuable data about the network sessions occurring within the network, such as source and destination IP addresses, port numbers, and protocols used. This session data is useful for understanding traffic patterns, volume, and usage.

The unauthorized usage of "Tcpdump" tool indicates that the malicious insider was attempting to obtain all information within datagrams passing through a specific interface on the network. Tcpdump allows users to capture packet data from a live network or read packets from a previously saved capture file. References := Cisco CyberOps - Module 3: Network Data and Event Analysis

The log in the exhibit is generated by a firewall. It shows a deny action taken on TCP traffic, specifying the source and destination addresses and ports, which is characteristic of firewall logs. Firewalls are designed to control incoming and outgoing network traffic based on predetermined security rules, and this log entry reflects the enforcement of such a rule.
References :=
Cisco's official documentation on firewall technologies and their log formats.