Book Image

Network Scanning Cookbook

By : Sairam Jetty
Book Image

Network Scanning Cookbook

By: Sairam Jetty

Overview of this book

Network scanning is a discipline of network security that identifies active hosts on networks and determining whether there are any vulnerabilities that could be exploited. Nessus and Nmap are among the top tools that enable you to scan your network for vulnerabilities and open ports, which can be used as back doors into a network. Network Scanning Cookbook contains recipes for configuring these tools in your infrastructure that get you started with scanning ports, services, and devices in your network. As you progress through the chapters, you will learn how to carry out various key scanning tasks, such as firewall detection, OS detection, and access management, and will look at problems related to vulnerability scanning and exploitation in the network. The book also contains recipes for assessing remote services and the security risks that they bring to a network infrastructure. By the end of the book, you will be familiar with industry-grade tools for network scanning, and techniques for vulnerability scanning and network protection.
Table of Contents (10 chapters)

How to detect operating system

Nmap uses TCP/IP stack fingerprinting for OS detection.This is done by crafting custom TCP and UDP packets and analyzing their responses. After generating various such probes and comparing the results to the Nmap-os-db database of more than 2,600 known OS fingerprints and provides the OS version. The fingerprint provides details such as the vendor name, OS name, OS generation, device type, and also their Common Platform Enumeration (CPE) representation. Nmap also provides an option for the user to submit the fingerprint obtained if it is not present in the Nmap database of operating signatures:

  • -O (Enable OS detection): This enables OS detection for an Nmap scan. This flag further has options that can be used in conjunction with it.
  • --osscan-limit: This option will reduce the scan time when a list of hosts is being scanned by skipping the hosts...