Scanning Your Network for Vulnerabilities: Steps and Remediation

Scanning Your Network for Risks and Vulnerabilities: What to Do When You Find Them

In today’s cybersecurity landscape, scanning your network for vulnerabilities is a critical step in maintaining a secure IT infrastructure. Vulnerability scanning allows you to identify weaknesses in your systems that could be exploited by attackers. Once identified, these risks must be addressed to prevent potential breaches or disruptions.

This guide explains how to scan your network for risks and vulnerabilities, the types of vulnerabilities to look for, and what actions to take once vulnerabilities are discovered.

1. Understanding Vulnerability Scanning

Vulnerability scanning involves using automated tools to assess your network, systems, and applications for security weaknesses. These tools identify potential vulnerabilities, such as unpatched software, misconfigurations, open ports, and insecure protocols that could be exploited by cybercriminals.

There are several types of vulnerability scans, each focusing on different areas of the network:

• Network scans check for vulnerabilities in routers, firewalls, servers, and other network devices. They assess things like open ports, insecure network protocols, and outdated firmware.
• Application scans focus on vulnerabilities in web applications, databases, and APIs. They look for issues such as SQL injection, cross-site scripting (XSS), and insecure authentication mechanisms.
• Operating system scans check for vulnerabilities in the underlying OS, such as missing patches, outdated software, or misconfigurations.
• Internal scans focus on identifying risks within the organization’s internal network, ensuring that devices inside the firewall are secure.
• External scans are conducted from outside the network perimeter to identify vulnerabilities that are visible and accessible from the internet.

Regular scanning is essential because networks and systems change over time, and new vulnerabilities emerge as software and hardware components age or are misconfigured.

2. Choosing the Right Tools for Scanning

There are many vulnerability scanning tools available, ranging from open-source solutions to commercial products, each offering varying degrees of coverage and analysis.

Popular tools include:

• Nessus: A comprehensive network vulnerability scanner that identifies weaknesses in your systems, from outdated software to insecure network configurations.
• OpenVAS: An open-source vulnerability scanner that covers a wide range of network devices and services.
• Qualys: A cloud-based security platform that offers in-depth scanning for network, applications, and systems vulnerabilities.
• Nikto: A web server scanner that identifies known vulnerabilities in web servers, such as outdated server software, insecure headers, and configuration issues.

The key is to select a tool that fits your network’s size, complexity, and specific needs. Many organizations use a combination of scanning tools to ensure comprehensive coverage across different environments.

3. Conducting a Network Vulnerability Scan

Once you’ve selected a tool, the next step is conducting a vulnerability scan. The process typically follows these steps:

• Define the scope of the scan: Before starting, clearly define which systems, applications, and devices will be scanned. Ensure that critical infrastructure, such as firewalls, routers, servers, and cloud environments, is included. Internal and external scans should be conducted regularly to cover both internal risks and those visible from outside the network.

• Configure scan settings: Most tools allow you to configure specific scan parameters. For example, you can choose to scan for specific vulnerabilities, such as open ports or weak encryption algorithms, or run more comprehensive scans that check for a broader range of risks.

• Run the scan: Depending on the size of your network and the scope of the scan, this process can take some time. Network vulnerability scans may impact system performance, so they are typically conducted during off-hours or scheduled maintenance windows to minimize disruptions.

• Review the scan results: Once the scan is complete, review the report generated by the tool. This report will include a list of detected vulnerabilities, categorized by severity (e.g., critical, high, medium, low). For each vulnerability, the report provides details such as the affected system, the nature of the vulnerability, and recommendations for remediation.

4. Types of Vulnerabilities to Look For

A vulnerability scan typically reveals a variety of security risks, including:

• Unpatched software: One of the most common vulnerabilities is outdated software or missing security patches. Attackers often exploit known vulnerabilities in unpatched software to gain unauthorized access or execute malicious code. Ensuring that all systems are up to date with the latest patches is essential.

• Misconfigurations: Misconfigured devices or systems can leave an organization exposed to attacks. This could include weak encryption settings, default passwords, or improperly configured firewalls that allow unwanted traffic through.

• Open ports: Scans will check for open ports that are exposed to the internet or internal network. Open ports that are not required for business operations can be exploited by attackers to gain access to the network. Limiting open ports to only those that are necessary reduces the attack surface.

• Weak authentication mechanisms: Poorly implemented authentication systems, such as weak passwords or outdated authentication protocols, present significant security risks. Vulnerability scans help identify insecure login mechanisms and recommend stronger alternatives like multi-factor authentication (MFA).

• Insecure network protocols: Using outdated or insecure network protocols, such as FTP or HTTP instead of encrypted alternatives like SFTP or HTTPS, can expose sensitive data to interception. Vulnerability scans flag the use of such protocols and suggest switching to secure options.

5. What to Do When Vulnerabilities Are Found

Once a scan identifies vulnerabilities, the next step is to prioritize and remediate them.

• Prioritize vulnerabilities by severity: Not all vulnerabilities require immediate action. Focus on critical and high-severity vulnerabilities first, as these are the most likely to be exploited by attackers. These vulnerabilities often relate to unpatched software, exposed services, or misconfigurations that can lead to direct system compromise.

• Apply patches and updates: For vulnerabilities related to unpatched software, the first step is to apply the necessary updates. Ensure that the software, firmware, or operating systems are updated to the latest versions. A solid patch management process helps keep systems secure.

• Fix misconfigurations: Misconfigurations in firewalls, routers, or applications should be corrected according to the scanner’s recommendations. This could involve adjusting firewall rules, disabling unused services, or enforcing secure configurations.

• Close unnecessary ports: Review open ports that were identified as unnecessary or risky. Disable or close these ports to prevent unauthorized access. Ensure that only essential services are allowed through the network perimeter.

• Enhance authentication security: If weak authentication mechanisms are identified, take steps to strengthen them. Implement MFA, enforce stronger password policies, and ensure that secure authentication protocols like OAuth or SAML are in place.

• Re-scan after remediation: After vulnerabilities have been addressed, it’s important to run another scan to verify that the issues have been resolved. This ensures that remediation efforts were successful and that no new vulnerabilities were introduced during the process.

6. Continuous Monitoring and Best Practices

Vulnerability scanning is not a one-time activity. Cyber threats evolve, and new vulnerabilities are constantly discovered, so continuous monitoring and regular scans are essential.

• Schedule regular scans: Conduct vulnerability scans at regular intervals—weekly, monthly, or quarterly, depending on the size and complexity of the network. Ensure that scans are integrated into the security workflow, especially after major infrastructure changes or software updates.

• Keep tools up to date: Regularly update the scanning tools themselves to ensure they have the latest vulnerability databases and are equipped to detect the newest risks.

• Follow a patch management process: Implement a systematic patch management process to keep software, firmware, and operating systems up to date. Patches should be tested and applied promptly to minimize exposure.

• Train staff on security practices: Human error can lead to misconfigurations or delays in patching. Regular training on security best practices, including proper configuration management and incident response, helps maintain a secure environment.

Regularly scanning your network for vulnerabilities is an essential part of any cybersecurity strategy. By identifying risks early and remediating them promptly, you can significantly reduce the chances of a security breach. Prioritizing vulnerabilities, applying patches, fixing misconfigurations, and continuously monitoring the network will ensure that your systems remain secure in the face of evolving cyber threats.