Best Port Scanning Tools For Ethical Hackers

Introduction

Port scanning tools are software applications designed to scan and analyze the open ports on a computer system or network. These tools are used to identify which ports are active, closed, or filtered.

By scanning a system’s ports, network, and security admins can determine what potential vulnerabilities exist, and which measures to take to secure the system against unauthorized access.

There are many tools available for port scanning including free and paid options. In this post, I will be going over a list of available tools providing features with pros and cons.

But before I get into the details of the tools let’s quickly look at what ports are and how port scanning works.

What is a Port and How Port Scanning Works

A port is a 16-bit number used in TCP/IP (Transmission Control Protocol/Internet Protocol) networking in combination with the IP Address of a computing device for applications and services to communicate between devices.

A port is a virtual endpoint for communication between devices. Similar to how an IP address is used to identify each computer in a network, the port number is used to identify each service on a computer.

Port scanning is a method that involves the examination of a network’s open and closed ports to identify vulnerabilities and access. Port scanning works by actively or passively accessing a port to find out if it is active or closed.

Port scanning is used by network and security professionals to assess the security of a network and identify vulnerabilities. Using this information they will harden the configuration to make it difficult for malicious actors to exploit network access weaknesses.

Below are links to posts getting in details of ports and port scanning.

Now with the basics in place let’s get into the main purpose of this post: Provide a list of tools.

Some of the most famous hacking tools in the market are Nmap (Network Mapper), Nessus, Nikto, Kismet, NetStumbler, Acunetix, Netsparker, Intruder, Nmap, Metasploit, Aircrack-Ng, etc.

Port Scanning Techniques: Pros and Cons

Port scanning tools are divided into different categories based on the type of scan they perform. Following are the main scan categories.

Category	Description	Pros	Cons
TCP Port Scan	TCP port scans are used to determine which TCP ports are open on a system. TCP port scans are the most basic type of port scan and are used to identify which services and applications are running on a system.	Quick and simple to perform; ideal for basic security assessments.	Can be detected by security systems; not as effective for more complex scans.
UDP Port Scan	UDP port scanning is used in a similar manner to TCP scans, with the goal to identify open, close,d and filtered ports.	Good for identifying services that use the UDP protocol; can be less likely to be detected by security systems.	May not provide as much information as a TCP port scan; may be blocked by firewalls.
Stealth Port Scan	Stealth port scanning techniques are used to evade firewalls and intrusion detection systems (IDS) by concealing the scan as normal network traffic.	Advantages: Conceals the scan as normal network traffic, making it less likely to be detected by security systems.	More complex and time-consuming to perform; requires a deeper understanding of networking and security concepts.

Each category of port scanning strategy has its own pros and cons. In general, TCP port scans are the simplest while stealth port scans are more complex and sophisticated.

Which one will you choose? It depends on your use case and the type of vulnerability you are trying to discover.

At this time I do want to note that port scanning tools are used by both ethical and malicious hackers. It is important to understand the ethical and legal considerations of hacking.

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Most Popular Port Scanning Tools & Utilities

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Importance of Port Scanning Tools for Network Security

Port scanning tools play a crucial role in network security by by identify open and accessible ports on their systems and networks. While security administrators can determine which services and systems are running on the network and assess their security impact, hackers may use this information to exploit said target network.

You should use port scanning tools to improve your network’s security. Following are some benefits a network owner will gain from planned testing.

1. Compliance: Use port scanning for ensuring that the network is in compliance with industry standards and compliance. Common regulations are Payment Card Industry Data Security Standard (PCI DSS) and the Health Insurance Portability and Accountability Act (HIPAA).
2. Detect unauthorized services: Find information on unauthorized services accessible without permission. Or malware installed on a target system using open ports to communicate.
3. Form network baseline: Create a baseline of the network to compare with future scans to identify planned network changes or potential security incidents.
4. Identify potential attack targets: Port scanning can identify open ports and services that are possible targets for attackers.
5. Vulnerability assessment: Quickly identify open ports and services, to identify known vulnerabilities.

What are the Legal Restrictions on Port Scanning

The legality of port scanning can vary depending on the jurisdiction and the specific circumstances of the scan. One should always follow ethical guidelines for conducting port scans and other related activities.

Read my post on Ethical and Legal Considerations of Hacking.

Listed below are some important considerations around port scanning:

1. Permission from the owner: Advanced permission allowing port scanning should always be obtained from the system owner.
2. Restrictions on use: Some tools and methods may be restricted by local jurisdictions or prohibited by by the terms of service of the tool.
3. Security & Performance Impacts: Port scanning may temporarily negatively impact the security and performance of the targeted network. Consider this before executing a live scan.

Conclusion

Port scanning tools are software programs used to identify and map open ports on a computer or network. They are used for a variety of purposes, including network security assessments, vulnerability assessments, and penetration testing.

The above list shows some of the most popular and widely used port scanning tools.