How to Perform a Vulnerability Scan: 4 Steps

Network vulnerability scanning is the process of pinpointing weaknesses and vulnerabilities across a network, including evaluating network assets like computers and other devices — any potential target that could be exploited by threat actors should be included in these scans. 

The basic steps for performing a network vulnerability scan are:

1. Plan and define the scope of the scan
2. Identify vulnerabilities
3. Perform analysis
4. Mitigate identified vulnerabilities

Notably, vulnerability scans are also frequently used by attackers seeking vulnerabilities to exploit. Even when attackers are unable to access a network internally, vulnerability scans can be conducted from the outside. This is the key reason organizations often choose to perform scans while logged in as network users and without access to a network. 

For more information, also see: Why Firewalls are Important for Network Security

How Does a Vulnerability Scan Work?

Typically, vulnerability scans are conducted by an organization’s IT department, although some organizations outsource this process to a third-party security service provider. Organizations that operate within sectors like finance and banking often perform vulnerability scans through approved vendors to adhere to industry regulations.

In most instances, organizations will deploy a vulnerability scanning tool to automate much of the vulnerability scanning process. These scanners start from the endpoint of the person inspecting the attack surface being examined. The scanner compares details about the target attack surface to a known security hole database, attempting to exploit each vulnerability as it is discovered. 

Vulnerability scans fall into two overarching categories: authenticated and unauthenticated. During an unauthenticated scan, testers behave like an intruder who does not have trusted access to the network. This reveals vulnerabilities that attackers can exploit without needing to log into the network. 

Authenticated vulnerability scans are conducted while logged into the network as a trusted user (or an attacker who has gained access by pretending to be a trusted user). 

Within these two categories, a variety of different network vulnerability scans can be conducted, including:

• Network based assessments scan wired and wireless networks.
• Database scans look at databases in an effort to prevent attacks like distributed denial of service (DDoS), SQL injection, and brute force attacks.
• Web application scans evaluate web applications and their source codes.
• Host-based scans examine server workstations and other network hosts, including related ports and services.

For more information, also see: Data Security Trends

How to Perform a Vulnerability Scan in 4 Steps

There are many viable options for performing a vulnerability scan. These four steps are likely to be a part of any properly run vulnerability scan, but you may need to adjust some aspects of these steps (or add additional steps) based on your unique organizational needs. 

1. Plan and define the scope of the scan

Before you start to conduct a vulnerability assessment of your network, it’s a good idea to define the parameters of the scan. These steps can help narrow the scope of your scan:

• Identify where your most sensitive data is stored across the network
• Hunt down hidden sources of data
• Identify the servers that run mission-critical applications
• Determine which systems and networks you want to assess
• Check for misconfigured ports
• Check for misconfigured processes
• Create a map of the entire network infrastructure, including digital assets and connected devices
• Select an automated vulnerability scanning tool that offers the features you need — for example, reporting capabilities

Be sure to create a centralized place for information sharing information across your security team.

2. Identify vulnerabilities

As you work through the process of scanning the network for vulnerabilities, take careful notes. Your list should include as much detail as possible about any underlying security threats.

The easiest and quickest way to identify specific vulnerabilities is through the use of an automated vulnerability scanning tool, though some organizations also opt to conduct a manual penetration test, a step that can help you validate findings (and reduce false positives). 

3. Perform analysis

Utilize the reporting features built into your automated vulnerability scanning tool. Ideally, these reports should include risk ratings and vulnerability scoring that allows you to prioritize which vulnerabilities to address first. A common scoring system used by these tools is the common vulnerability scoring system (CVSS), which assigns a numerical value to each identified risk. 

Depending on the automated scanning tool you are using, you may need to run multiple scans across different network segments. This is especially true when the network is large or contains a mix of internal and external endpoints. 

4. Mitigate or remediate identified vulnerabilities 

Once you have identified and prioritized vulnerabilities, it’s time to determine how best to mitigate these risks. Mostly, you’ll want to address vulnerabilities through either remediation or mitigation. 

Remediation

Remediation is a process for fully eliminating a vulnerability to prevent exploitation by threat actors. Sometimes, remediation is as simple as refreshing security tool protocols or updating products. Other conditions call for the skills of advanced security analysts.

Mitigation

In cases where the solution for fixing or patching a vulnerability is not clear, mitigation tactics can be applied to at least reduce the likelihood of an attack. Later, as tools evolve or more information becomes available, these vulnerabilities can be completely remediated. 

Typically, a mitigation approach will involve additional tools like antivirus software, real-time antivirus scanners, additional firewalls, or tools used within advanced security solutions like predictive AI threat detection. Each of these tools can help bridge the gap between known and unknown network risks. 

For more information, also see: How to Secure a Network: 9 Steps

When Should you Perform a Vulnerability Scan?

IT teams are advised by many oversight bodies to scan internal and external systems at least quarterly, but ideally, monthly assessments should be considered, even if they are not comprehensive in scope. Assessing parts of the network that house particularly sensitive data on a regular basis is a good best practice. 

Bottom line: How to Perform a Vulnerability Scan

By following these four steps, you’ll have a much better sense of the vulnerabilities located throughout your network. Vulnerability scans can help you prioritize risks to ensure your team is tackling the most urgent exploit risks sooner, rather than later. 

Whether you perform quarterly or monthly scans, you can feel certain that the vulnerability scanning process is worthwhile. Without the insight provided by this process, security teams are less equipped to adequately assess an organization’s actual risk.

On a related topic, also see: Top Cybersecurity Softwar