Introduction

Conducting penetration testing is a vital procedure for organizations to uncover vulnerabilities within their systems, networks, and applications. As discussed earlier, an array of command line tools aids in this endeavor by evaluating the security status of a designated system.

This text delves into three such command line tools: Network Mapper (Nmap), Metasploit, and Nessus. Additionally, it provides insights into the distinctive features and capabilities of each tool.

Network Mapper (Nmap)

Nmap serves the purpose of identifying active hosts, open ports, and services within a network. It offers a variety of scanning techniques, such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and SYN scanning, also referred to as half-open scanning. SYN scanning is a method employed by malicious hackers to ascertain the status of a communication port without establishing a complete connection. These scanning techniques are frequently utilized to evaluate the attack surface of a network and identify potential entry points for potential attackers.

Capabilities

Within the command line Nmap has several capabilities, including:

• -sP: Pings a scan to discover active hosts.
• -sS: TCP SYN scans and discovers open ports.
• -sU: UDP scans and identifies open UDP ports.
• -sV: Version detection determines service versions.
• -A: Aggressive scan mode combines various scan types.

Features

Being an open-source tool, Nmap maintains its significance in network reconnaissance, serving as an essential resource for identifying potential security threats. Its proficiency lies in uncovering vulnerabilities and potential entry points that could be exploited by malicious actors. Nmap excels in executing version detection, revealing the software supporting open ports.

Nmap stands out as a versatile tool designed for thorough network scanning and assessment of security attributes. Its command-line interface offers a comprehensive range of scanning methods, enabling users to identify active hosts, accessible ports, and services across networks. Nmap skillfully handles TCP, UDP, and SYN scans, providing testers with the means to evaluate the vulnerability landscape of the target. The tool’s robust aggressive scan mode combines various scanning techniques, leading to comprehensive and detailed outcomes.

Metasploit

Moving on to Metasploit, it stands out as another command-line tool specifically employed for penetration testing. As mentioned earlier, Metasploit is a robust framework designed to aid penetration testers in the creation, testing, and execution of exploit code against a remote target. This encompasses the development of payloads and auxiliary modules that can be utilized to compromise systems, acquire access, and gather information. Metasploit extends its functionality to post-exploitation activities as well.

Capabilities

Within the command line, Metasploit’s capabilities include:

• use <module>: Select an exploit or module.
• set <option> <value>: Set a variety of options for the selected module.
• exploit or run: Execute the selected exploit or module.
• sessions: List all active sessions and connections.
• Post module: Used for post-exploitation activities, like privilege escalation or data collection.

Features

Metasploit stands as a potent framework geared toward both penetration testing and the exploitation of vulnerabilities. Through its command-line interface, it furnishes an array of functionalities catering to the development, assessment, and execution of exploit code. The framework boasts an extensive repository comprising exploits, payloads, and auxiliary modules, equipping testers with the means to compromise systems and attain access.

The use command within Metasploit handpicks specific exploits or modules, while the set command facilitates configuration adjustments. Initiating exploits or modules against target systems is streamlined with the exploit or run command. Metasploit’s post-exploitation capabilities come to the fore, facilitating tasks like elevating privileges and gathering data. The framework’s adaptability and comprehensive repository of exploits position it as a favored choice among ethical hackers, enabling them to proficiently appraise and safeguard systems.

Nessus

Last is Nessus, you previously learned that Nessus is used for scanning commercial vulnerabilities to identify security issues within networks, systems, and applications. Nessus is typically managed through a web interface, but it can also be controlled through the CLI using the Nessus command. Nessus provides a wide range of vulnerability checks, it then reports any potential weaknesses that could be exploited by attackers. 

Capabilities

There are several other commands that can be used in Nessus including:

• nessuscli scan list: List any existing scan configurations.
• nessuscli scan new: Creates a new scan configuration.
• nessuscli scan launch: Launch a scan using a specific configuration.
• nessuscli report list: List all available scan reports.
• nessuscli report export: Export a scan report in a variety of formats.

Features

Nessus is a comprehensive commercial vulnerability scanner equipped with powerful capabilities for identifying security issues. Its CLI, complementing the web-based interface, allows users to manage scans and report in an efficient manner.

Nessus provides a comprehensive suite of pre-built vulnerability checks, enabling in-depth assessments of networks, systems, and applications. The tool’s functionality includes the use of scan list and scan new commands for the creation and management of scan configurations. The scan launch command initiates scanning processes, and the report list and report export commands assist in analyzing and exporting scan reports.

Nessus’s strength lies in its capability to detect vulnerabilities across diverse environments. Its support for various report formats enhances its value as a tool for organizations aiming to proactively address security concerns. The versatility and robust features of Nessus make it a valuable asset in the proactive management of security in varying IT landscapes.

Conclusion

Nmap, Metasploit, and Nessus stand out as powerful command-line tools, each serving distinct roles within the realm of penetration testing. Nmap excels in network reconnaissance, Metasploit focuses on exploiting vulnerabilities, and Nessus provides extensive capabilities for vulnerability assessment. When employed responsibly and ethically, these tools play a significant role in enhancing the security posture of systems and networks.

It is crucial to emphasize that while these tools are valuable in penetration testing, their usage must always adhere to ethical standards and legal regulations. Unauthorized scanning and testing can result in legal consequences. Furthermore, penetration testing should be conducted only with proper authorization and a thorough understanding of the systems being tested.