Pentest vs Vulnerability Scan: Which Do You Need for Security?

When it comes to securing your startup, two buzzwords often stir confusion: penetration testing and vulnerability scanning. Both are essential to a comprehensive security strategy — but they serve different purposes, are conducted differently, and yield different outcomes.

This guide breaks down the differences between penetration testing and vulnerability scanning, when to use each, and how to maximize the value from both.

Vulnerability Scanning: The First Line of Defense

A vulnerability scan is a proactive security measure aimed at identifying known weaknesses in your application or systems. Automated tools scan for configurations, software versions, and other parameters and check them against databases of known vulnerabilities.

How It Works

1. Automated Tools — Use tools like Nessus, Qualys, and OpenVAS to scan systems regularly. These tools can identify missing patches, atypical configurations, and low-hanging fruit vulnerabilities.
2. Frequency — Ideally, run these scans regularly: monthly or quarterly, preferably after major developments or infrastructure changes.
3. Output — You'll get a report outlining vulnerabilities, their severity, and some recommended actions.

Limitations

• Not Comprehensive — Vulnerability scans identify known issues but miss many contexts and exploit paths.
• Limited Human Insight — Scanners can't understand the business logic of your application or test your security posture under real attack scenarios.

Penetration Testing: The Reality Check

A penetration test (pentest) is a simulated cyberattack performed by skilled security professionals. It aims to exploit weaknesses, determine the potential impact of a breach, and provide you with actionable insights into your security posture.

How It Works

1. Human Expertise — Skilled testers use a combination of automated tools and manual testing techniques. They mimic the tactics and techniques used by real attackers.
2. Phases of Pentesting
   • Planning and Reconnaissance — Identifying targets, understanding potential attack paths, and defining the scope.
   • Exploitation — Actively trying to exploit vulnerabilities to gain access and escalate privileges.
   • Reporting — Providing a detailed report that includes findings, methodology, proof of exploit, and remediation recommendations.
3. Frequency — Conduct pentests annually, or if there are significant changes in your infrastructure, to ensure ongoing security.

Benefits

• Real-World Attack Simulation — Understand how a true attacker would exploit your systems.
• Customized Testing — PRIDe-based selective testing based on your infrastructure and business logic.

Limitations

• Cost — Pentests generally cost more ($5,000–$20,000+) than automated scans and may be harder to fit into smaller budgets.
• Snapshot in Time — Reflects your security at one point; should be complemented with regular vulnerability scans.

When to Use Each

Use Vulnerability Scanning When:

• You need a baseline overview of security weaknesses.
• Regular monitoring for compliance and standards.
• Costs or resource constraints prevent immediate pentesting.
• Automated testing fits into your DevOps cycle seamlessly.

Use Penetration Testing When:

• You’re preparing for a major product launch.
• Your users are being acquired by enterprise customers requiring audits.
• There are significant changes in your infrastructure, or you've faced incidents in the past.
• You need to fulfil SOC 2 Type II or similar requirements.

Conclusion

Vulnerability scanning and penetration testing are both critical components of a robust security program. While scans can catch known vulnerabilities, pentests can identify deeper, contextual issues before attackers can take advantage of them.

To choose wisely, balance the need for regular scanning with the necessity of occasional, comprehensive pentesting.

Need help? Talk to our team to get started with your security assessment today.