In today’s digital landscape, organisations rely on internet-facing systems to support their operations, from websites and email servers to cloud applications and remote access tools. However, these systems also represent prime targets for cybercriminals looking for weaknesses to exploit. An external network vulnerability scan is a crucial security measure that helps businesses detect and address vulnerabilities before they can be exploited.
By proactively scanning public-facing assets, businesses can identify risks such as unpatched software, misconfigured security settings, and exposed services. These scans play a key role in maintaining a strong cybersecurity posture, ensuring that an organisation’s perimeter defences remain robust against evolving threats.
This guide explores the importance of vulnerability scanning of external networks, how these scans work, and best practices for implementing them effectively.
What Are External Network Vulnerability Scans?
An external network vulnerability scan is a security assessment designed to identify weaknesses in publicly accessible systems, such as web applications, email servers, VPN gateways, and cloud services. These scans evaluate the security of an organisation’s external perimeter, helping to detect vulnerabilities that could be exploited by cybercriminals attempting to gain unauthorised access.
Unlike internal vulnerability scans, which focus on threats inside the corporate network, external scans assess security risks from the outside in, simulating the perspective of an external attacker. By scanning for weaknesses in internet-facing assets, businesses can take proactive steps to patch vulnerabilities before they become entry points for cyberattacks.
Key Elements of an External Network Vulnerability Scan
- Scanning publicly accessible systems: Assessing websites, remote access tools, and other externally facing services.
- Identifying outdated or vulnerable software: Detecting unpatched applications that could be exploited.
- Checking for misconfigurations: Reviewing firewall rules, access controls, and security policies.
- Assessing exposure of sensitive data: Identifying potential leaks in publicly accessible files or APIs.
Regular external scanning is an essential part of network security and should be integrated into a broader vulnerability management strategy. Learn more about FoxTech’s external penetration testing services for a deeper security assessment.
How External Scans Identify Potential Entry Points
Cybercriminals often target organisations by looking for weaknesses in their external infrastructure. An external network vulnerability scan helps identify these weak points before they can be exploited.
1. Detecting Open Ports and Unnecessary Services
Every open port on an organisation’s network represents a potential attack surface. External scans detect exposed ports and services that may be unintentionally accessible, such as:
- Unsecured remote desktop access (RDP) or SSH connections.
- Open database ports, which should be restricted to internal use.
- Unnecessary file-sharing services that could leak sensitive data.
2. Identifying Outdated or Vulnerable Software
Attackers frequently exploit known vulnerabilities in outdated software. External scans assess:
- Web applications running on outdated content management systems (CMS).
- Unpatched email and VPN servers with known security flaws.
- Third-party plugins or extensions that introduce security risks.
3. Finding Security Misconfigurations
Misconfigured security settings can leave networks exposed. Scans help detect:
- Default credentials that have not been changed, making them easy to exploit.
- Improperly configured firewalls allowing unrestricted access.
- Weak SSL/TLS encryption, exposing sensitive data to interception.
By identifying these vulnerabilities early, businesses can reduce the risk of cyberattacks and data breaches.
Tools Commonly Used for External Vulnerability Scans
Organisations use a variety of tools to perform external network vulnerability scans. Some of the most commonly used tools include:
1. FoxTech Assure Vulnerability Scanning
Rather than relying solely on automated tools, FoxTech’s vulnerability scanning services combine advanced scanning techniques with expert analysis. This approach ensures that businesses receive accurate, actionable insights while reducing false positives.
👉 Learn more about FoxTech’s external security assessments
2. OWASP ZAP
OWASP ZAP (Zed Attack Proxy) is an open-source tool for finding vulnerabilities in web applications through automated and manual testing. When used .
3. Nessus
Nessus is a widely used vulnerability scanner that detects a range of security issues, from misconfigurations to known software vulnerabilities. It provides detailed reports to help organisations prioritise and remediate risks.
4. Qualys
Qualys offers cloud-based external scanning services that continuously assess an organisation’s internet-facing assets, helping security teams maintain visibility and compliance.
5. OpenVAS
An open-source scanning tool, OpenVAS helps identify security vulnerabilities in public-facing infrastructure, making it a cost-effective option for smaller organisations.
While automated tools provide valuable insights, professional security assessments ensure that vulnerabilities are correctly prioritised and remediated.
Best Practices for Conducting External Vulnerability Scans
To maximise the effectiveness of an external network vulnerability scan, businesses should follow best practices to ensure accurate results and effective remediation.
1. Schedule Regular Scans
Cyber threats evolve quickly, so businesses should conduct scans at least monthly to detect emerging vulnerabilities. Additional scans should be initiated when:
- Deploying new public-facing applications.
- Making significant network changes.
- Responding to newly disclosed vulnerabilities.
2. Secure Proper Permissions
Ensure that scans are conducted with the approval of IT security teams to prevent unintended disruptions. Penetration testing providers, like FoxTech, follow ethical guidelines to ensure safe and authorised scanning.
3. Interpret Results Effectively
Not all detected vulnerabilities pose an immediate risk. It’s crucial to:
- Prioritise critical and high-risk vulnerabilities for immediate remediation.
- Validate findings to reduce false positives.
- Use intelligent scoping to focus on the most critical threats.
4. Implement Security Fixes Promptly
Once vulnerabilities are identified, businesses should:
- Apply patches and updates to mitigate software vulnerabilities.
- Adjust firewall rules to close unnecessary open ports.
- Strengthen authentication mechanisms, such as enforcing multi-factor authentication (MFA).
By following these best practices, businesses can effectively reduce their external attack surface and enhance overall security.
Why External Scans Are Critical for Network Security
Regular external vulnerability scanning is essential for identifying and mitigating cyber threats before they lead to security incidents. By conducting routine scans, organisations can:
1. Prevent Data Breaches
Scanning for vulnerabilities helps detect security gaps before they can be exploited, reducing the risk of data breaches and financial losses.
2. Maintain Compliance
Industries such as finance, healthcare, and retail require external security assessments to comply with regulations like GDPR and ISO 27001. Routine scans ensure organisations meet compliance requirements.
3. Reduce Exposure to Cyber Threats
Cybercriminals constantly scan for weaknesses in public-facing systems. Proactively scanning your external network ensures that vulnerabilities are addressed before attackers can exploit them.
4. Strengthen Overall Security Posture
A well-structured external vulnerability scanning strategy provides organisations with continuous insight into their security perimeter, allowing them to improve defences against cyber threats.
Conclusion
An external network vulnerability scan is a vital component of modern cybersecurity, helping businesses identify and remediate weaknesses in internet-facing systems. These scans detect open ports, misconfigurations, and outdated software, ensuring that organisations can proactively address security risks before they are exploited.
Regular scanning, combined with expert-led penetration testing services, enhances an organisation’s ability to detect and respond to threats. FoxTech offers comprehensive external vulnerability scanning and security assessments to help businesses stay protected.
