What is Vulnerability Scanning?

How does the vulnerability scanning process work?

The vulnerability scanning process comprises the following steps:

• Discovery of assets and inventory to identify all of the systems, servers, endpoints, and applications in the organization's IT network.
• Vulnerability scans by leveraging scanning tools to perform authenticated or unauthenticated scans to detect internal and external weaknesses.
• Vulnerability validation by comparing the results of the scan against known vulnerability databases like CVE, NVD, or CISA KEV.
• Analyzing and prioritizing vulnerabilities using standard metrics such as CVSS, likelihood of exploits, and impact on business.
• Remediation of the detected vulnerabilities in the network by implementing patching and software updates, endpoint configuration and hardening, and other manual workarounds - in the absence of patches.
• Generate reports of the vulnerability scanning process for compliance audits and create actionable steps for the ITOps and SecOps teams to follow.
• Continuous monitoring and rescanning to verify fixes and continuously monitor the network for imminent vulnerabilities.

Why is vulnerability scanning important?

Vulnerability scanning defends enterprise networks from cyber risks by identifying vulnerabilities proactively, before attackers can exploit them. Furthermore, industry regulations mandate cybersecurity compliance as an essential aspect of business functions. In such instances, regular vulnerability scanning is of utmost importance to ensure business continuity and adherence to compliance.

Here are some reasons why vulnerability scanning matters for enterprises:

• Early detection of vulnerabilities and other exploitable weaknesses, such as unpatched software, weak passwords, open ports, and other misconfigurations, before they can be exploited by threat actors.
• Adhering to regulatory compliance frameworks such as GDPR, PCI DSS, and HIPAA requires periodic vulnerability scans in the network, as mandated by these compliance policies.
• Holistic IT visibility into the network and the managed endpoints with regular scans to reveal shadow IT, expired licenses, and EOL operating systems that pose high security risks and would be overlooked.

What are the different types of vulnerability scans?

Vulnerability scans can be classified into various types based on multiple factors such as the level of access, location, and the technique used.

Based on Access level or Credential Level

• Unauthenticated Scans simulate what an external attacker views the network as, and what vulnerabilities can be identified, without the use of credentials.
• Authenticated Scans make use of credentials to log in to the network and deeply analyze the configurations, managed software, and file systems.

Based on Network Location

• External Scans assess the internet-facing systems such as cloud systems, web servers, DNS, and other systems that are open to public use. These scans aim to identify open ports or other insecure web applications that can be exploited by threat actors.
• Internal Scans assess the internal networks for insider threats, lateral movements, malware, or other compromised systems that can cause security issues to the integrity of the network.

Based on Technique

• Active Scans directly send requests to the systems or devices to interact with and gather the required data related to potential misconfigurations, unnecessary open ports, and other unattended or exposed services. Since these scans are intensive, they end up consuming more bandwidth - hence, these are best suited as periodic scans.
• Passive Scans, contrary to active scanning, this mode of vulnerability scanning observes the network traffic and identifies vulnerabilities based on the data flow and communication channels - without actively interacting with the endpoints and hence doesn't affect the system performance.

What are the different types of vulnerability scanners?

1. Network-based Scanners

These vulnerability scanners inspect the routers, switches, firewalls, and other edge devices to identify unattended open ports, insecure protocols, and misconfigurations.

2. Host-based Scanners

These types of vulnerability scanning tools are installed on devices or servers to analyze system-level, OS-level, and configuration vulnerabilities, as well as zero-day vulnerabilities and missing patches.

3. Application Scanners

These scanners are focused on detecting vulnerabilities in web and mobile applications, and cloud apps for flaws such as outdated software, vulnerable plugins, SQL injection, cross-site scripting (XSS), authentication bypass, and insecure APIs.

4. Database Scanners

Database vulnerability scanners identify weaknesses within databases (SQL or non-SQL) and ensure that sensitive information, such as credentials, default accounts, or financial data, is safe and secure.

5. Cloud & Container Scanners

When it comes to cloud environments and containerized workloads such as Docker or Kubernetes, these vulnerability scanning tools analyze for misconfigurations, vulnerable images, policy violations, or overprivileged Identity Access Management (IAM) users.

Recommended frequency and schedule for vulnerability scanning

Scheduling scans properly is as important as scanning the network for vulnerabilities. Since vulnerability scanning can sometimes consume resources, it is important to create schedules that balance the asset criticality, the capacity of the resources, and the risk level.

What are the common challenges in vulnerability scanning?

Vulnerability scanning, however crucial it is for enterprises, comes with a set of challenges that make the implementation process demanding.

• False Positives or negatives cause alarm and confusion among the concerned teams, primarily due to the misinterpretation of vulnerabilities. In some cases, missed detections can lead to security issues, opening up the network for potential threats.
• Impact of scanning on system performance is another challenge that IT teams need to take care of. Active scans, being resource-intensive, can consume excessive network bandwidth and system resources, thereby creating performance gaps. Hence, these scans should be planned periodically, based on the employee's or the organization's working hours.
• Managing credentials securely for authenticated scans can be difficult. Since many organizations use a mix of multiple operating systems and platforms, each of these requires different authentication mechanisms - domain credentials, API tokens, and so on, making it particularly difficult to manage credentials for large organizations.
• Alert fatigue is a common challenge that IT teams across industries face, particularly when it comes to managing multiple vulnerability scanning tools with hundreds of alerts incoming; highly severe or critical ones often get buried in the lot. This makes prioritization very difficult and delayed. Moreover, multiple constant alerts cause burnout among the IT teams, making them trust the scanner outputs less.

What are the best practices for effective vulnerability scanning?

• Maintain an accurate asset inventory through regular scanning to identify shadow IT, hardware, software, and cloud assets. Continuous asset discovery through agent-based scans and network scans improves the quality of vulnerability scans.
• Classify vulnerability scanning based on business criticality of assets, i.e., servers, public-facing systems, or other business critical endpoints must be scanned frequently and at scheduled intervals.
• Use multiple scan types since a single scan type cannot capture the complete spectrum of vulnerabilities. It is important to cover both internal and external environments, and hence it is essential to combine network-based, host-based, internal, and external scans.
• Automate remediation post scans to enhance the vulnerability management process. Vulnerability scanning tools with integrated patch management and other unified endpoint management modules shorten the mitigation times, especially for low-risk or redundant vulnerability types.
• Verify mitigations with rescans to ensure that the vulnerabilities are remediated across all of the endpoints. It also clears up false positives from being populated in the dashboard and helps keep the systems audit-ready for compliance.
• Leverage risk-based prioritization with the risk-based vulnerability management process. Instead of relying solely on CVSS, incorporate multiple data points, such as asset exposure, availability of exploits, business criticality, and threat intelligence, to ensure a holistic mitigation approach.

FAQs on Vulnerability Scanning

1. What is vulnerability scanning?

Vulnerability scanning is the process of scanning IT networks to identify and assess security flaws and vulnerabilities in the network, systems, and applications, and mitigate them before threat actors can exploit them. Vulnerability scanning forms the first step of the vulnerability management process.

2. How does a vulnerability scan work?

A vulnerability scan works by scanning the IT network, endpoints, and applications for known vulnerabilities. The identified vulnerabilities are then assigned risk scores for prioritization and documented using reports.

3. What are the main types of vulnerability scans?

The main types of vulnerability scans include:

• Network-based scans to detect open ports, system misconfigurations, or insecure protocols.
• Host-based scans to assess the vulnerabilities on the system level, OS-level, and configurations.
• Credential-based scans that either simulate the network as an external attacker does or make use of credentials to log into the network and deeply analyze the configurations and other flaws.

4. Which tool is used for vulnerability scanning?

ManageEngine Vulnerability Manager Plus is a leading tool that can be used to scan for vulnerabilities by enterprises. With a built-in patch management module, this tool also helps mitigate the detected vulnerabilities with patching and other configuration deployments.

5. What is the difference between vulnerability scanning and penetration testing?

Vulnerability scanning is a scheduled, preventive method that scans the network for known vulnerabilities, zero-day exploits, and misconfigurations.

Penetration testing, on the other hand, is a manually simulated attack on the network, designed to exploit the vulnerabilities, if any, and assess the impact of a real-world attack.

While vulnerability scanning is typically performed on a fixed schedule, usually weekly or monthly, penetration testing is conducted quarterly or annually on the network or codebase.

6. What are the best practices for vulnerability scanning?

Some of the best practices for vulnerability scanning include:

• Keeping the asset inventory updated for better quality of the scan data.
• Using a mix of authenticated, unauthenticated, active, and passive scans.
• Prioritizing vulnerability remediation based on risks and not just a particular metric.
• Using integrated solutions that offer patching and vulnerability scanning.
• Continuous scanning and re-scanning after patch deployment, new device additions, and any major changes.

7. What are the benefits of vulnerability scanning?

Regular vulnerability scanning bolsters the network from vulnerabilities and strengthens the organization's security posture by identifying exploitable vulnerabilities, reducing the risk of breaches, and helping adhere to compliance requirements.

About the author

Anupam Kundu is a Product Specialist at ManageEngine in the Unified Endpoint Management and Security suite. With a background in digital marketing, his expertise includes creating technical and long-form content for SEO and user education in the IT and cybersecurity domain.