Book Image

Nmap 6: Network Exploration and Security Auditing Cookbook

Book Image

Nmap 6: Network Exploration and Security Auditing Cookbook

Overview of this book

Nmap is a well known security tool used by penetration testers and system administrators. The Nmap Scripting Engine (NSE) has added the possibility to perform additional tasks using the collected host information. Tasks like advanced fingerprinting and service discovery, information gathering, and detection of security vulnerabilities."Nmap 6: Network exploration and security auditing cookbook" will help you master Nmap and its scripting engine. You will learn how to use this tool to do a wide variety of practical tasks for pentesting and network monitoring. Finally, after harvesting the power of NSE, you will also learn how to write your own NSE scripts."Nmap 6: Network exploration and security auditing cookbook" is a book full of practical knowledge for every security consultant, administrator or enthusiast looking to master Nmap. The book overviews the most important port scanning and host discovery techniques supported by Nmap. You will learn how to detect mis-configurations in web, mail and database servers and also how to implement your own monitoring system. The book also covers tasks for reporting, scanning numerous hosts, vulnerability detection and exploitation, and its strongest aspect; information gathering.
Table of Contents (18 chapters)
Nmap 6: Network Exploration and Security Auditing Cookbook
Credits
About the Author
Acknowledgement
About the Reviewers
www.PacktPub.com
Preface
References
Index

Detecting open relays


Open relays are insecure mail servers that allow third-party domains to use them without authorization. They are abused by spammers and phishers and they present a serious risk to organizations because public spam blacklists may add them and affect the entire organization, which depends on e-mails reaching its destination.

This recipe shows how to detect open relays by using Nmap.

How to do it...

Open your terminal and enter the following command:

$ nmap -sV --script smtp-open-relay -v <target>

The output returns the number of tests that passed, and the command combination used:

Host script results:
| smtp-open-relay: Server is an open relay (1/16 tests)
|_MAIL FROM:<[email protected]> -> RCPT TO:<[email protected]>

How it works...

The script smtp-open-relay was submitted by Arturo 'Buanzo' Busleiman, and it attempts 16 different tests to determine if an SMTP server allows open relaying. If verbose mode is on, it also returns the commands...