Active reconnaissance is a computer attack where hackers communicate with a target system to collect information. The process involves probing a network for weaknesses, such as open ports or other possible entry points that include vulnerable routers.

“Reconnaissance” is a military term used to refer to missions into enemy territory to gather relevant information before carrying out an attack. In computer security, active reconnaissance is often the first step attackers take to gain insights into how best to enter a target network.

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Active Reconnaissance

Is Active Reconnaissance Only for Attackers? Can Ethical Hackers Use It?

No and yes, respectively. Many whitehat hackers use active reconnaissance to assess clients’ networks. They use it to detect system vulnerabilities and possible entry points. They then address these weaknesses before attackers can.

What Are the Widely Used Active Reconnaissance Tools?

After answering the question “What is active reconnaissance?” you may be wondering what tools it requires. Ethical hackers use various applications to interact with computers on a target network. They gather data that may not be available through other means using programs such as:

Metasploit

Metasploit is a penetration testing tool. While many threat actors use it to carry out attacks, whitehats employ it to develop intrusion detection/prevention systems (IDSs/IPSs), too. Since it is Ruby-based, users can write, test, and run exploit codes that allow them to conduct targeted analyses of security vulnerabilities.

Nmap

Nmap is a network mapper. It is a free and open-source scanner for networks that users employ to discover hosts and detect system details, including currently running programs. It performs several types of scans against a wide range of IP addresses that send packets to a target network and analyzes its responses.

Nessus

Developed by Tenable, Inc., Nessus is a remote vulnerability scanning tool that identifies vulnerable applications running on a system. It returns details on how threat actors can exploit weaknesses. While this tool does not come free of charge, it does produce a vast number of useful data that security teams can use, making it a worthy investment.

OpenVAS

Open Vulnerability Assessment System (OpenVAS) is also widely used for vulnerability scanning and management. All of the components of OpenVAS run tests against clients’ computers, providing users comprehensive information about how guarded servers are against known attacks. OpenVAS was a subset of Nessus before it was commercialized, so it bears much of the latter’s functionality.

Nikto

Nikto is a web server scanner that works much like Nessus and OpenVAS. It identifies several vulnerabilities in web servers. Unlike the active reconnaissance tools that threat actors use, Nikto is highly detectable by an IDS, so it is ideal for ethical hacking purposes.

Passive versus Active Reconnaissance, What’s the Difference?

The main difference between active and passive reconnaissance lies in the method. In active reconnaissance, the attackers actually interact with a target network and so leave trails. In passive reconnaissance, they do not actively engage with systems, leaving fewer or no clues of their presence.

Since the attacks’ methods differ, their results also vary. Active reconnaissance may be riskier but can generate more useful information. Passive reconnaissance yields more unreliable data and is often time-consuming.

Penetration testers use both to gather a more comprehensive overview of a network’s cybersecurity. They use them to identify and report vulnerabilities and carry out the necessary steps to prevent further attacks. Security usually involves setting up web application firewalls (WAFs) that can adapt to an organization’s growing needs, including both on-premise and cloud-based applications.


In an ideal world, systems must not have any vulnerability that would allow hackers with malicious intent to infiltrate and modify them. While active reconnaissance is a form of hacking, it is also an excellent means to fortify network protection.

Active reconnaissance tools can help ensure system protection at all times from all possible angles. Paired with an effective firewall and IDS/IPS solution, it can improve an organization’s cybersecurity posture. Now that you know the answer to the question “What is active reconnaissance?” you have taken the first step in ensuring you control who can see or access your network.