Scanning Networks

Scanning Networks is a critical phase in ethical hacking engagements where the penetration tester systematically examines network topology, identifies active systems, and discovers potential vulnerabilities. This process follows the initial footprinting phase and provides detailed technical intelligence about target systems. Network scanning employs various methodologies including TCP/UDP port scanning, OS fingerprinting, and service enumeration. During TCP scanning, techniques like SYN scans send TCP packets with specific flags to determine if ports are open, closed, or filtered. UDP scanning assesses availability of services like DNS or DHCP. Tools such as Nmap provide comprehensive scanning capabilities including stealth scans, version detection, and script automation. Masscan offers high-speed scanning for large networks, while Angry IP Scanner provides user-friendly interface for quick host discovery. The scanning process typically follows these steps: 1. Host discovery - identifying live systems using ICMP, ARP, or TCP methods 2. Port scanning - determining open ports and services 3. Service enumeration - identifying running applications and versions 4. OS detection - determining operating systems through TCP/IP stack behavior 5. Vulnerability mapping - correlating discovered services with known weaknesses Ethical hackers must conduct scanning activities carefully to avoid disrupting networks or triggering security alerts. Techniques like slow scanning, distributed scanning, or using decoy IPs help minimize detection. Documentation during scanning is essential, recording all discovered hosts, services, and potential vulnerabilities. This data forms the foundation for subsequent penetration testing phases including vulnerability assessment and exploitation. Understanding network scanning is fundamental for CEH practitioners as it bridges reconnaissance and actual exploitation, providing the technical roadmap needed for effective penetration testing.

Scanning Networks is a critical phase in ethical hacking engagements where the penetration tester systematically examines network topology, identifies active systems, and discovers potential vulnerab…

Concepts covered: Network Scanning Concepts, Scanning Tools, Host Discovery, Port and Service Discovery, OS Discovery (Banner Grabbing/OS Fingerprinting), Scanning Beyond IDS and Firewall, Draw Network Diagrams