When it comes to a cyber attack, it’s a matter of if, not when. But there are many ways to reduce cyber risk, and one starts with your organization’s network. 

Hackers work around the clock, and your network is always connected to the internet, which introduces 24-hour risk — Protection needs to be constant. 

Enter continuous network scanning. 

What Is Continuous Network Scanning? 

Continuous network scanning involves monitoring for intrusions around the clock to reduce the likelihood that an IT system will be breached by bad actors to steal sensitive data. It also requires automatic alerts and reports that uncover the defense posture of the organization’s network, while indicating which employees could be a weak link in the security chain. 

Yearly or quarterly vulnerability scanning is no longer sufficient to detect risks in an IT system. An organization needs a proactive, 24×7 continuous defense to stand a chance against cybercriminals incessantly probing the network. 

That incessant probing can lead to a cyber attack, and if not detected, can stay within a system for hundreds of days. On average, it takes a company 287 days to identify and contain a data breach, according to IBM’s 2022 Cost of a Data Breach. With continuous network scanning, that number can be greatly reduced, which in turn reduces potential damage — financial or otherwise. 

How Does a Network Scan Work? 

Network scanning is done by pinging a network and getting a response. This can be done continuously, 24×7, to determine if there’s any irregularities with the pings and identify vulnerabilities. Many organizations utilize a tool, or agent, to conduct these pings and check for specific irregularities within specific points in the network. 

Network scans fall into two categories, passive network scanning and active network scanning. Passive scanning, or packet sniffing, tracks data packets moving through an organization’s network. Active scanning uses pings or test packets to search for specific irregularities and actively examines the results. 

However, not all network scans are the same. There are four major types that an organization can deploy. 

Four Types of Network Scans 

1. External Vulnerability Scans 

This type of scan looks at your network from the hacker’s perspective. It scans external IP addresses and domains, probing for vulnerabilities in internet-facing infrastructure to determine which ones can be exploited.  

External vulnerability scans are best used to verify the strength of your externally facing services. It helps identify weaknesses in your perimeter defenses, such as a firewall. These scans reveal not only your vulnerabilities, but also the list of ports that are open and exposed to the internet. While external scans are like external penetration tests, they are different in their methodologies.  

Looking at your network from this point of view lets you easily identify the most pressing issues within your network, including any services or new servers that have been set up since the last scan to see if they present any new threats to your organization. 

2. Internal Vulnerability Scans 

Performed from a location with access to the internal network, internal vulnerability scans are more complex than external ones, because there are also more potentially vulnerable assets within your organization. This scan will discover and catalog your core IP-connected endpoints, such as laptops, servers, peripherals, IoT-enabled machines, and mobile devices. 

Internal vulnerability scanners check these endpoints for vulnerabilities due to misconfigurations or unpatched software, so you can prioritize the devices that require immediate attention to properly secure the network. 

Internal scans are best used for patch verification, or when you need to provide a detailed report of vulnerabilities within the network. When analyzing the data, take note of trends such as the top missing patches and the most vulnerable machines. 

Performing internal scans on a regular basis is a proactive approach to protecting your network from known vulnerabilities and helps you gain useful insight into your patch management process. 

3. Host-Based Agent Scans 

host-based agent lives on the device itself and tracks active processes, applications, Wi-Fi networks, or USB devices that don’t conform to company policies. It can then flag the user or IT team to fix the issue. In some cases, the agent can close the vulnerability by blocking the malicious action. 

Host-based agents monitor system activity for signs of suspicious behavior, including repeated failed login attempts, changes to the system registry, or backdoor installations. 

A host-based agent is not a complete solution. That’s because visibility is limited to a single host, and attacks aren’t seen until they have already reached the host. The passive nature of host-based technologies means they are best suited to use in conjunction with the other types of security scans listed here to take advantage of complementary strengths. 

4. Penetration Testing Tools 

IT teams can go beyond passive scanning with penetration testing tools. In penetration testing (often called pen tests) security experts simulate how malicious hackers may attempt to infiltrate your network. 

These attacks help verify the effectiveness of your cybersecurity efforts, identify any potential weak spots, and test the human response capabilities of your security team and IT partners. Valuable and effective penetration testing tools are vital to gauge your system’s security posture. 

Types of penetration testing tools include: 

  • Clear Box Tests. Your organization provides penetration testers with a variety of security information relating to your systems to help them easily find vulnerabilities. 
  • Blind Tests. Your company provides penetration testers with no security information about the system being penetrated with the goal of exposing vulnerabilities that would otherwise go undetected. 
  • Double-Blind Tests. Penetration testers attempt to find vulnerabilities in external-facing applications, such as websites, that can be accessed remotely. 
  • Internal Tests. Penetration testing takes place on-premises and focuses on security vulnerabilities that someone within your organization may use for their advantage. 

Penetration testing, the most active form of network scanning, can be critical to reducing cyber risk and patching vulnerabilities. It shows your organization where and how a malicious attacker might exploit your network, allowing you to mitigate weaknesses before a real attack occurs. 

How Arctic Wolf Can Help with Network Scanning and Vulnerability Management 

As part of Arctic Wolf Managed Detection and Responsethe Arctic Wolf agent connects to the network and continuously collects information from the IT environment. This agent and 24×7 monitoring leads to endpoint threat detection, actionable endpoint intelligence, advanced asset inventory and operational metrics, host-based vulnerability management, security controls benchmarking, and managed containment.  

In addition, Arctic Wolf is powered by the Concierge Security Team who works with your organization’s IT department to not only analyze intelligence but develop action plans to improve your security posture and continue your security journey. 

Learn more about how an MDR solution provides continuous internal monitoring with our MDR Buyer’s Guide. 

Explore how to secure your network thoroughly with “How to Secure Your Internet-Facing Infrastructure Today. 

Originally published on the Arctic Wolf Blog, December 21, 2022.