The world is becoming 'smarter' and increasingly digital daily, which can only mean one thing. To ensure that all systems and applications are secure, a sound mechanism must be in place to identify security threats before malicious actors exploit them.
Cyber threats are becoming more advanced every day, which means an organization has to be on its toes to maintain its security posture. Vulnerability scanning is one of the best ways to identify and mitigate potential vulnerabilities within a system or application.
In this article, I’ll explain open-source vulnerability scanning, describe the different types, and identify some of the best free, adaptable scanner options available to Linux users.
What is a Vulnerability Scanner?
A vulnerability scanner is a unique tool developed to model the security posture of a system, network, or application by identifying known vulnerabilities. These tools automate the security auditing process by scanning websites and cloud applications for any signs of vulnerabilities. In this respect, they assist an organization in building its defense by providing depth against hostile actors.
Such scanners ensure a prioritized list of cybersecurity vulnerabilities that need to be fixed, elaborating on the nature of each and the steps required for fixing them. Advanced tools provide automated patching for seamless remediation.
These vulnerabilities need to be addressed without delay. Unpatched security vulnerabilities expose a system to cyberattacks, enabling hackers to exploit these weaknesses. This can cause monumental monetary losses and reputation damage.
CISA states, "Timely patching is essential to protect systems from threats."
Vulnerability scanning tools utilize substantial databases of known vulnerabilities to scan systems for risks systematically. Like antivirus software and intrusion detection systems, scanners significantly maintain optimal data and network security.
Type of Scanners
Vulnerability scanners can fit into four broad categories, each aiming at different areas of network security:
Data-based Vulnerability Scanners
Today, organizations operate in an information-intensive environment where a considerable amount of critical data must be safeguarded. Whenever sensitive information gets lost, the impacts on a strong reputation and high economic losses are unbearable.
Data-based vulnerability scanners attack database vulnerabilities. They hunt for issues such as Patch deficiencies, weak passwords, and poor configurations. Furthermore, they may give the user live feeds about a possible vulnerability. As a result, these tools empower the user to adopt an immediate and combative attitude towards threats in network security.
Network-based Vulnerability Scanners
Organizational networks are continuously becoming interconnected, increasing the risk of security hazards. Network-based scanners assist in discovering vulnerabilities in both wired and wireless networks. They constantly monitor probable threats in real time and help organizations take essential precautions to avoid security risks before they can be exploited.
Host-based Vulnerability Scanners
Though security is an inherent feature in most web hosting platforms, a few bugs can still be traced. The host-based vulnerability scanners installed on every host in the system give full-fledged information about possible vulnerabilities due to insider threats or attacks from outside. By constantly monitoring each host, these scanners enable organizations to remain proactive on network security.
Cloud-based Vulnerability Scanners
Due to the remote work trend, cloud-based vulnerability scanners have gained immense momentum as companies become increasingly dependent on cloud services. Vulnerability Scanning cloud-based tools focus on detecting vulnerability issues in the cloud environment, including applications and web assets. Since the cloud environment is dynamic, periodic cloud security checks must be performed by an organization to reduce emergent threat factors effectively.
Understanding the Importance of Vulnerability Scanning
The deployment of scanning tools to identify vulnerabilities plays a vital role in several ways:
- Proactive Threat Management: Vulnerability assessment and scanning enable an organization to keep identifications and patches ahead of malicious actors' exploits.
- Regulatory Compliance: Most industries operate under strict regulatory requirements that require periodic security assessments. In scenarios like these, applying a vulnerability scanner proves beneficial in keeping organizations compliant and negating potential penalties.
- Security Posture: It improves the systematic identification and one-by-one remediation of the various vulnerabilities present within an organization, ultimately enhancing its security posture and minimizing the chances of a successful cyber-attack.
- Cost Savings: Finding vulnerabilities earlier saves the organization millions of dollars in costs related to data breaches, regulatory fines, and reputational damage.
IBM reports that the average data breach cost reached $4.45 million in 2023- a significant amount when considering the financial aspect of cybersecurity.
Top Free and Open-Source Vulnerability Scanners
Several excellent free and open-source vulnerability scanners are available to Linux users. Our top choices include:
OpenVAS
OpenVAS is a powerful open-sourced vulnerability scanner. It has broad scanning capabilities and utilizes a robust database of known vulnerabilities to conduct in-depth system assessments. The output from OpenVAS can be very detailed, thus allowing an organization to prioritize remediation efforts accordingly.
Nessus Essentials
Though Nessus is a commercial tool, it has a free version called Nessus Essentials. This limited version can scan up to 16 IP addresses and provides access to most of the essential functions of vulnerability scanning. In general, Nessus has an easy-to-use interface and a large vulnerabilities database. Security experts admit it is one of the best tools for finding vulnerabilities.
Nmap
Nmap is not strictly a vulnerability scanner but a robust network exploration tool that can also perform security scanning. Its scripting engine allows users to develop custom scripts to identify vulnerabilities in networked systems. Nmap is widely used for network mapping and security auditing.
Nikto
Nikto is a web server scanner specialized in identifying vulnerabilities within web applications. The tool performs comprehensive checks against various web server configurations and finds outdated software, possible security misconfigurations, and known vulnerabilities.
W3AF
W3AF is an open-source web application security scanner designed to identify vulnerabilities in web applications. This tool has different plugins for deep testing and helps secure web applications against common threats like SQL injection and cross-site scripting.
Arachni
Arachni is a full-featured web application security scanner capable of mapping paths, input points, and topics in depth. It can perform different advanced scans and provide detailed reports that will help developers fix security issues that have been found efficiently.
Our Final Thoughts on the Importance of Linux Vulnerability Scanners
Open-source vulnerability scanning tools are a much-needed part of a modern cybersecurity strategy. By being informed of the tools available to Linux users and using them correctly, admins and organizations can enhance their security posture to effectively mitigate threats emanating from an increasingly complicated digital landscape. Regular vulnerability assessments are a best practice and a must in fighting criminal activities online.
