Uncovering Cyber Threats: The Beginners Guide to Vulnerability Scanning with Nessus, OpenVAS, Nmap, and Burp Suite

Vulnerability scanning is a vital part of any organization's cybersecurity strategy. It is a process that involves identifying potential vulnerabilities in your network or website and assessing the risks associated with them.

In this article, I will discuss the most effective ways to conduct a vulnerability scan on your network, including the best tools for the job and how to use them properly to conduct an effective scan.

Understanding Vulnerability Scanning

Before diving into the best practices for vulnerability scanning, it's important to understand what it entails. Vulnerability scanning is the process of identifying potential vulnerabilities in your network or website by scanning for known vulnerabilities and misconfigurations. It involves using specialized software tools to identify and report on any vulnerabilities that are found.

Effective Ways to Conduct a Vulnerability Scan

Determine Your Scope

Before starting a vulnerability scan, it's important to determine your scope. This will help you to identify the areas of your network or website that you need to scan. Consider the different types of assets you have, including servers, workstations, routers, and applications. Determine which of these assets are critical to your business operations and need to be scanned. This will help you to prioritize your efforts and ensure that you are focusing on the areas that are most important.

Choose the Right Tools

Choosing the right tools is essential for conducting an effective vulnerability scan. There are many different vulnerability scanning tools available, both commercial and open-source. Some of the most popular vulnerability scanning tools include:

Nessus

A commercial vulnerability scanner that is widely used in the industry. It has a comprehensive vulnerability database and can perform both internal and external scans.

Nessus can help identify numerous types of vulnerabilities, including:

Missing Patches: Nessus is excellent at identifying missing security patches, outdated software versions, and end-of-life applications.

Misconfigurations: Nessus can spot misconfigurations in network devices, operating systems, databases, and applications that may expose the system to potential attacks.

Policy Non-Compliance: Nessus checks systems against defined policy requirements, identifying any deviations or non-compliance that might pose a security risk.

OpenVAS

OpenVAS, short for Open Vulnerability Assessment Scanner, is an open-source tool used for comprehensive vulnerability scanning.

OpenVAS can help identify numerous types of vulnerabilities, including:

Network Vulnerabilities: OpenVAS can identify vulnerabilities related to insecure network protocols, poorly configured firewalls, and other network-related issues.

Web Application Vulnerabilities: OpenVAS can detect common web application vulnerabilities, such as SQL injection, Cross-Site Scripting (XSS), and Cross-Site Request Forgery (CSRF).

Host-Based Vulnerabilities: It can also spot vulnerabilities within the host, such as weak passwords, insecure file permissions, or malware presence.

Nmap

A network mapping and port scanning tool that can also be used for vulnerability scanning. It has a large user community and can be used to scan both internal and external networks.

Nmap can help identify numerous types of vulnerabilities, including:

Open Ports: Nmap can identify open ports on a network, revealing potential entry points for attacks.

Version Detection: Through its version detection capabilities, Nmap can find out-of-date software that could contain exploitable vulnerabilities.

Script-based Vulnerabilities: With its scripting engine, Nmap can identify more complex vulnerabilities using custom scripts, including detection of insecure configurations and weak encryption algorithms.

Burp Suite

A web application security testing tool that can identify vulnerabilities in web applications.

Burp Suite can help identify numerous types of vulnerabilities, including:

Injection Attacks: Burp Suite can detect vulnerabilities that could lead to injection attacks, such as SQL, OS, and LDAP injection vulnerabilities.

Cross-Site Scripting (XSS): It can identify XSS vulnerabilities where an attacker could inject malicious scripts into content viewed by other users.

Insecure Direct Object References (IDOR): Burp Suite can spot instances where an application exposes a reference to an internal implementation object.

Cross-Site Request Forgery (CSRF): It can also detect CSRF vulnerabilities where an end user could be tricked into performing an action they did not intend to.

Configure the Tools Properly

Once you have selected the right tools for your vulnerability scan, it's important to configure them properly. This includes setting the appropriate scan parameters and options, such as the target IP addresses and ports to scan. It's also important to configure the tools to comply with any legal and ethical requirements, such as obtaining permission to scan and ensuring that the scan does not disrupt normal business operations.

You should configure the vulnerability scanning tools to comply with any compliance or regulatory requirements that may apply to your organization. For example, if you are in the healthcare industry, you may need to comply with HIPAA regulations, which require periodic vulnerability scans of the IT infrastructure.

Additionally, configuring the tools to perform the appropriate scan type is also important. Some vulnerability scanners provide the option to perform different types of scans, such as a quick scan, a full scan, or a targeted scan. The choice of scan type depends on the scope of the scan and the resources available. A quick scan can be useful to quickly identify the most common and critical vulnerabilities, while a full scan can take a longer time but provide a more comprehensive report.

Interpret the Results of the Vulnerability Scan

Once the vulnerability scan is complete, the next step is to analyze the results and identify the vulnerabilities that need to be remediated. The vulnerability scan report typically lists all the vulnerabilities that were detected, their severity level, and the potential impact on the organization.

Interpreting the results requires a deep understanding of the vulnerabilities and their potential impact. The severity level of the vulnerability can be used to prioritize the remediation efforts. For example, a critical vulnerability that allows remote code execution may require immediate attention, while a low-level vulnerability that has a minimal impact on the system can be addressed later.

It is also important to validate the findings of the vulnerability scan. False positives and false negatives can occur, which can lead to incorrect remediation efforts. To avoid these errors, it is recommended to perform additional manual testing or conduct a re-scan of the assets to verify the results.

Conclusion

Vulnerability scanning is an essential part of any organization's cybersecurity strategy. By identifying potential vulnerabilities in your network or website, you can take steps to mitigate the risks associated with them. The most effective ways to conduct a vulnerability scan include determining your scope, choosing the right tools, configuring the tools properly, and interpreting the results. By following these best practices, you can ensure that your vulnerability scans are effective and that you are taking the necessary steps to protect your organization from cyber threats.