Organizations today face a rapidly evolving threat landscape, and as they plan their cybersecurity strategy and budgets, many may struggle with a key question: If I’m conducting regular vulnerability scans, and patching the vulnerabilities I identify, do I really need penetration tests as well?
The answer is yes.
While vulnerability scanning plays a vital role in identifying risks and vulnerabilities, relying solely on it for security creates blind spots. Penetration testing complements vulnerability scanning to give organizations a more thorough understanding of their security posture by testing the implementation of controls.
Below, we explore why both are necessary by focusing on:
- Depth of analysis vulnerability scans provide compared to pen tests
- Context surrounding the issues vulnerability scans uncover
- Human expertise required to assess which vulnerabilities present the most cause for concern
Depth and Quality of Analysis
Vulnerability scanners are invaluable for quickly detecting known vulnerabilities in systems, networks, and applications. They excel at broad coverage but operate within predefined parameters and do not test for the correct implementation of features and access. Their primary limitation relates to the depth of exploration beyond initial detection.
Penetration testing, on the other hand, complements the identification of those issues by simulating real-world attack scenarios. Penetration testers actively exploit vulnerabilities allowing analysts to evaluate:
- How deeply a system can be compromised
- Whether combinations of vulnerabilities create additional attack vectors
- The effectiveness of security measures, such as firewalls and endpoint protection
For instance, a scanner might detect an open port but it alone can’t determine if the open port could lead to unauthorized access. This is when a penetration tester comes in to try and exploit these areas to verify and evaluate potential impact.
Context Surrounding the Issues
Penetration tests also add a level of context to a vulnerability scan. While scans provide a list of vulnerabilities, often ranked by severity, they do not offer any insights into prioritization. Organizations therefore need to parse the findings without fully understanding the context behind these findings.
Penetration testing adds this critical context by:
- Identifying vulnerabilities that are most relevant to the organization’s environment (e.g., critical applications or sensitive data)
- Highlighting realistic attack paths (e.g., pivoting from a user account to an administrator)
- Providing insights into how existing safeguards might mitigate some vulnerabilities
For instance, a vulnerability scan might flag various low-priority items, but a follow-up penetration test could reveal that a seemingly minor issue, combined with poor internal segmentation, enables lateral movement to sensitive data, turning a low-priority item into a significant risk.
Ultimately, a penetration test is conducted by security professionals who understand that context matters and that not all vulnerabilities are considered equal.
Human Expertise is Required
Perhaps the most significant limitation of vulnerability scanners conducted by vendors who do not utilize a human-led solution is their automated nature. In other words, it is the human expertise that makes the most difference between vulnerability scanning and penetration testing. Trustwave’s Managed Vulnerability Scanning service is a pragmatic, human-led service where our SpiderLabs team runs vulnerability scans on your behalf.
Penetration testing brings in human expertise, where skilled security professionals:
- Assess risks and threats that stand a reasonable chance of exploitation, leveraging tactics used by actual threat actors (i.e., put themselves in the mindset of an intruder, create hypotheses on how it may be possible to exploit one or more vulnerabilities, and then test those hypotheses)
- Validate findings by exploiting vulnerabilities, reducing false positives
- Interpret scanner output with a strategic perspective, emphasizing vulnerabilities that genuinely threaten the organization
For example, a vulnerability scan might flag an outdated configuration, but a penetration tester will assess whether this vulnerability could be exploited to intercept data during transmission. This helps provide a more accurate assessment of the associated risk.
A Comprehensive Offensive Security Strategy
Trustwave’s argument is that vulnerability scanning and penetration testing each play a role in forming a comprehensive offensive security strategy.
Vulnerability scanning identifies known weaknesses and helps companies maintain sound security hygiene. Penetration testing complements vulnerability scans by adding in-depth analysis, contextual understanding, and human expertise. This layered approach increases operational resilience, ensuring that weaknesses are not just flagged but addressed with urgency and precision.
Trustwave offers expert services in both areas, helping you identify, prioritize, and eradicate weaknesses in your environment. To learn more about our vulnerability scanning and pen testing capabilities, and our CREST-certified team, visit our Penetration Testing page.
