Welcome to the fascinating world of Vulnerability assessment and Penetration testing (VAPT), a crucial domain in the field of cyber security. This post will take you behind the scenes of VAPT, revealing the strategies and tactics employed in Ethical hacking. The term Ethical hacking might appear as an oxymoron for some, but it is one of the best defensive strategies against potential cyber threats. The aim is to identify vulnerabilities and rectify them before malicious intruders can exploit them. In this journey, you may come across the term 'nan'. Although seemingly plain, this abbreviation stands for 'Not A Number', an ubiquitous placeholder in the realm of programming and testing, and can prove a pivotal element in VAPT processes.

Vulnerability Assessment and Penetration Testing: An Overview

Before delving into the specifics of the process, it is critical to understand what VAPT entails. The process has two major components: Vulnerability assessment (VA) and Penetration testing (PT). VA is the practice of identifying weaknesses in a system's defenses, while PT involves simulating a real-world hacking attempt to verify the existence and exploitability of these vulnerabilities.

Strategy and Tactics in Vulnerability Assessment

Vulnerability assessments are typically performed in four stages: planning & preparation, scanning, analysis, and remediation. During the planning phase, a complete understanding of the target system and its computational environment is acquired. The scanning phase, on the other hand, is where 'nan' often comes into play. Programmatic scanners such as Nessus or Nexpose are commonly used to scan the system for vulnerabilities. These tools flag any strange or anomalous data as 'nan', essentially signifying a potential security vulnerability that requires further inspection.

The analysis phase follows, where the identified vulnerabilities are assessed on various parameters like severity and exploitability. This stage often involves lurking through the vast seas of the internet for documented cases of similar exploits and their fixes. Finally, the remediation phase involves patching the vulnerabilities and retesting to ensure effectiveness.

The Intriguing Process of Penetration Testing

Penetration testing serves as the practical application of the findings from the Vulnerability assessment. It further strengthens the defense strategy by adding a real-world perspective. Just like VA, Penetration testing also follows a structured path – reconnaissance, scanning, gaining access, maintaining access, and covering tracks.

Reconnaissance involves gathering preliminary data or intelligence on the target system. This information can be anything from IP addresses to user and device details. The next phase utilizes tools analogous to those in Vulnerability assessment to scan for points of ingress – these will flag similar 'nan' alerts when a suspicious potential entrance is detected.

Gaining access involves making use of these vulnerabilities to infiltrate the system. Depending on the type of Penetration test, this might involve data theft, service disruption, or other disruptive actions. Maintaining access involves making the necessary arrangements to ensure persistent ability to reenter, typically to show the potential damage over time if vulnerabilities are not addressed. Finally, covering tracks ensures that the test leaves no trace, thus keeping the process ethical and under the radar.

In conclusion, VAPT is an essential part of maintaining a robust defense against the relentless onslaught of cyber threats in the digital world today. Delving behind the scenes reveals a meticulously detailed process involving a balacing act between defensive and offensive cyber security strategies. The seemingly mundane 'nan' plays a significant role in identifying potential threats, thus helping secure systems against potential breaches. Ethical hacking, despite its innocuous sounding name, plays a pivotal role in contemporary cyber security, forming the foundations for more secure digital infrastructures.