Skip to Content
Network Security Assessment
book

Network Security Assessment

by Chris McNab
March 2004
Intermediate to advanced
396 pages
11h
English
O'Reilly Media, Inc.
Content preview from Network Security Assessment

Chapter 14. Example Assessment Methodology

In this final chapter, I walk through a remote security assessment of a small network protected by a firewall. By reading through this process from start to finish, you will have a good understanding of the overall process. The exercise will identify, attack, and penetrate systems in a class-c network space, from my launch system on a remote network.

Network Scanning

Increasingly, network scanning is becoming a cyclic process, primarily due to the finite amount of time you have to perform a network security assessment exercise and the fact that most firewalls repel fast SYN port scans.

The best practice approach to network scanning is to undertake the following:

  • Initial network scanning to identify poorly protected hosts and common services

  • Full scanning to identify all remotely accessible TCP and UDP services

  • Low-level network testing to gain insight into firewall and host configuration

In this section I perform these tests against the target 192.168.10.0/24 network. By coming up against the hurdles placed in my way by firewalls and defensive mechanisms, you will see how my approach is applied to get accurate results.

Initial Network Scanning

In Example 14-1, I use nmap with the -sP option to perform an initial sweep of the target network and identify any obvious accessible hosts that are poorly protected. If I don’t specify the -PI option, nmap also sends TCP probes to port 80 of each host in the target range.

Example 14-1. Using nmap to perform ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.

Read now

Unlock full access

More than 5,000 organizations count on O’Reilly

AirBnbBlueOriginElectronic ArtsHomeDepotNasdaqRakutenTata Consultancy Services

QuotationMarkO’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.
Julian F.
Head of Cybersecurity
QuotationMarkI wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.
Addison B.
Field Engineer
QuotationMarkI’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.
Amir M.
Data Platform Tech Lead
QuotationMarkI'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
Mark W.
Embedded Software Engineer

You might also like

Network Security Strategies

Network Security Strategies

Aditya Mukherjee
CCNA Cyber Ops SECFND #210-250 Official Cert Guide

CCNA Cyber Ops SECFND #210-250 Official Cert Guide

Omar Santos, Joseph Muniz, Stefano De Crescenzo

Publisher Resources

ISBN: 059600611XErrata Page