Penetration testing and security assessments are necessities for businesses today. With the rise of cyber and computer-based crime in the past few years, penetration testing has become one of the core aspects of network security. It helps in keeping a business secure from internal as well as external threats. The reason that penetration testing is a necessity is that it helps in uncovering the potential flaws in a network, a system, or an application.

Moreover, it helps in identifying weaknesses and threats from an attacker's perspective. Various inherent flaws in a system are exploited to find out the impact they can cause to an organization and to assess the risk factors to the assets as well. However, the success rate of a penetration test depends mostly on the knowledge of the tester about the target under test. Therefore, we generally approach a penetration test using two different methods: black-box testing and white-box testing. Black-box testing refers to a scenario where there is no prior knowledge of the target under test. Therefore, a penetration tester kicks off testing by collecting information about the target systematically. By contrast, in the case of a white-box penetration test, the penetration tester has enough knowledge about the target under test, and they start by identifying known and unknown weaknesses of the target. Generally, a penetration test is divided into seven different phases, as follows:

• Pre-engagement interactions: This phase defines all the pre-engagement activities and scope definitions – basically, everything you need to discuss with the client before the testing starts.
• Intelligence gathering: This phase is all about collecting information about the target under test by connecting to the target directly, and passively, without connecting to the target at all.
• Threat modeling: This phase involves matching the information detected with the assets to find the areas with the highest threat level.
• Vulnerability analysis: This involves finding and identifying known and unknown vulnerabilities and validating them.
• Exploitation: This phase involves taking advantage of the vulnerabilities found in the previous stage and typically means that we are trying to gain access to the target.
• Post exploitation: The actual task to be performed on the target, which might involve downloading a file, shutting down a system, creating a new user account on the target, and so on, are parts of this phase. Generally, this phase describes what you need to do after exploitation.
• Reporting: This phase includes summing up the results of the test in a file and the possible suggestions and recommendations to fix the current weaknesses in the target.

The seven stages just mentioned may look more natural when there is a single target under test. However, the situation completely changes when a vast network that contains hundreds of systems are to be tested. Therefore, in a case like this, manual work is to be replaced with an automated approach. Consider a scenario where the number of systems under test is precisely 100, and all systems are running the same operating system and services. Testing every system manually will consume much time and energy. Situations like these demand the use of a penetration testing framework. Using a penetration testing framework will not only save time but will also offer much more flexibility regarding changing the attack vectors and covering a much more comprehensive range of targets through the test. A penetration testing framework will eliminate additional time consumption and will also help in automating most of the attack vectors, scanning processes, identifying vulnerabilities, and, most importantly, exploiting the vulnerabilities, thus saving time and pacing a penetration test. This is where Metasploit kicks in.

Metasploit is considered one of the best and most used widely used penetration testing frameworks. With a lot of rep in the IT security community, Metasploit not only caters to the needs of penetration testers by providing an excellent penetration testing framework, but also delivers very innovative features that make the life of a penetration tester easy.

Mastering Metasploit, Fourth Edition aims to provide readers with insights into the legendary Metasploit Framework and specifically, version 5.0. This book focuses explicitly on mastering Metasploit with regard to exploitation, including writing custom exploits, porting exploits, testing services, conducting sophisticated client-side testing, evading antivirus and firewalls, and much more.

Moreover, this book helps to convert your customized attack vectors into Metasploit modules, and covers use of Ruby to do this. This book will not only help advance your penetration testing knowledge but will also help you build programming skills while mastering the most advanced penetration testing techniques.