What Is Vulnerability Scanning?
Vulnerability scanning is an automated process that systematically examines IT systems, software, and network infrastructure to identify known security weaknesses, misconfigurations, or outdated software versions that could be exploited by attackers.
It’s a core part of a proactive cybersecurity strategy not just for large enterprises, but for any organisation that manages sensitive data or depends on reliable systems.
How Vulnerability Scanning Works
Vulnerability scanning tools use a continuously updated database of known threats and system weaknesses. They scan systems using:
- Credentialed scans: Deeper scans using system-level login credentials, often for internal systems.
- Non-credentialed scans: External scans that simulate how an attacker might view your network from the outside.
After scanning, the tool provides:
- A list of vulnerabilities
- Severity levels (e.g. low, medium, high, critical)
- Recommended remediation actions.
How It Helps Identify Risks
- Highlights Known Security Gaps
Scanners detect outdated software, unpatched operating systems, weak configurations (e.g. open ports, default passwords), and insecure protocols. - Supports Regulatory Compliance
Vulnerability scanning is often a requirement under frameworks like Cyber Essentials, ISO 27001, and GDPR (if you process personal data). - Reduces Attack Surface
Regular scanning allows you to fix issues before they’re exploited, significantly lowering your risk of breach. - Feeds into Risk Management
Results help your IT or MSP prioritise patching, firewall configuration, or system upgrades based on actual threat exposure.
Checklist: What to Scan and How Often
Core Areas to Scan
Area | Examples |
Servers & Endpoints | Windows, Linux servers; staff laptops/desktops |
Network Devices | Routers, firewalls, switches, wireless access points |
Applications | Web apps, CMS (e.g. WordPress, Joomla), internal tools |
Cloud Infrastructure | Microsoft 365, Google Workspace, AWS, Azure settings |
Databases | SQL, MySQL, PostgreSQL version and exposure review |
Open Ports & Services | Scan for unnecessary or vulnerable services running |
Credentials & Permissions | Check for weak passwords, default admin accounts |
Recommended Scan Frequency:
Type of Scan | Frequency | Notes |
Internal Network Scan | Monthly | Checks servers, devices, internal infrastructure |
External Network Scan | Monthly or quarterly | Simulates outsider’s view — required for compliance |
Web Application Scan | After every update or monthly | Especially important for public-facing websites |
Credential Scan | Monthly | Identifies internal configuration weaknesses |
Cloud Config Audit | Quarterly or after major change | Covers SaaS misconfigurations, permissions, MFA |
Patch Verification Scan | After patch cycles (weekly/monthly) | Verifies patches have resolved vulnerabilities |
Best Practices for Effective Scanning
- Prioritise critical vulnerabilities first, especially those with known exploits (e.g. CVSS score 7.0+).
- Act on findings promptly vulnerability scans are only helpful if they result in remediation.
- Document scanning schedules and remediation timelines for audit trails and compliance.
- Use both automated tools and human oversight, especially when interpreting complex or false-positive findings.
- Integrate with patch management many modern MSPs and internal teams now align vulnerability results directly with patch automation workflows.
Common Vulnerability Scanning Tools
- Open Source / Freemium:
- OpenVAS (Greenbone)
- Nikto (for web apps)
- Nmap (for port scanning)
- Commercial:
- Nessus (Tenable)
- Qualys
- Rapid7 InsightVM
- Microsoft Defender for Endpoint (built into many M365 plans)
Why Vulnerability Scanning Matters for UK Organisations
Vulnerability scanning is not just a compliance checkbox, it’s one of the most effective and cost-efficient ways to stay ahead of cyber threats.
If you’re not scanning regularly, you’re essentially relying on hope as your security policy.