Certified: The CISSP Prepcast

Welcome to The Bare Metal Cyber CISSP Prepcast. This series helps you prepare for the ISC squared CISSP exam with focused explanations and practical context.
In this episode, we will explore the concepts of test coverage and measurement—two essential elements for evaluating the quality and completeness of your security testing processes. While implementing security controls and running assessments are important, they are not enough by themselves. You must also ensure that those tests are thorough, that they cover all relevant areas, and that the results provide meaningful insights. That is where the ideas of test coverage and measurement come into play. They help answer the questions: Are we testing everything we should? And are our tests actually working?
Let us start by unpacking the meaning of test coverage and measurement in the context of cybersecurity. Test coverage refers to the extent to which your security tests evaluate systems, applications, networks, and controls. It is a measure of how much of your environment has been assessed and to what depth. Coverage can apply to code, infrastructure, access controls, configurations, or any other area where vulnerabilities might exist. Measurement, on the other hand, involves quantifying the results of testing. It looks at how effective the tests are, what areas remain untested, how many vulnerabilities were discovered, and how thoroughly each layer of your security program has been evaluated.
These two concepts work together. Coverage ensures that testing is broad and deep. Measurement helps you understand the results and make decisions. Together, they form the foundation of an efficient and mature security testing program. When used properly, test coverage and measurement reduce the risk of blind spots, improve compliance, and drive continuous improvement.
So, why is comprehensive test coverage so important? The answer lies in the complexity of modern IT environments. Organizations operate a wide range of systems—servers, endpoints, cloud infrastructure, mobile apps, web platforms—and each of these introduces potential vulnerabilities. Without full coverage, critical weaknesses may go undetected simply because they were never tested in the first place. Poor coverage creates blind spots, and attackers are always looking for areas that defenders have overlooked.
Comprehensive coverage ensures that all relevant systems, configurations, and controls are evaluated. This includes both the obvious targets—like externally facing websites—and the less visible ones, like internal business applications or back-end databases. Coverage also includes testing different user roles, transaction types, and system states. It is not enough to test a login page—you must also test what happens after login, how sessions are handled, how errors are managed, and how access is revoked.
Strong test coverage supports compliance, too. Many regulations require organizations to validate that their security measures are working as intended. This means you need to show not only that tests were performed, but also that they covered the right areas. Comprehensive testing helps meet these obligations by demonstrating that security is being taken seriously and that the entire environment is being reviewed on a regular basis.
Test coverage also supports risk management. By testing all the areas where vulnerabilities might exist, you can prioritize mitigation efforts more effectively. If coverage is shallow or inconsistent, it is difficult to know where the most serious threats lie. But with broad and deep coverage, risk becomes easier to measure, communicate, and address. Ultimately, better coverage leads to a stronger security posture, greater confidence, and improved organizational resilience.
Now that we understand why coverage matters, let us look at how it is measured. Measuring test coverage begins with defining what needs to be tested. This includes identifying all systems, applications, endpoints, networks, and data flows. Once the scope is clear, you can develop coverage criteria—these are the benchmarks that describe what complete testing looks like for each item in scope.
Security frameworks can help here. They provide standardized criteria and best practices that organizations can use to assess coverage. Examples include the N I S T Cybersecurity Framework, the O W A S P Testing Guide, and the I S O Twenty Seven Thousand One series. These frameworks define the types of tests that should be performed and the areas that should be assessed.
Tools also play a key role. For application testing, code coverage tools measure what percentage of code has been executed during testing. In vulnerability management, scanning tools report on which systems were scanned, how many vulnerabilities were found, and what severity levels were assigned. Test case tracking systems record which test scenarios have been executed and which ones remain pending.
Another technique is checklist-based assessment. This involves using structured lists to document whether specific security requirements were tested. For example, a checklist might ask: Was multi-factor authentication tested? Were access permissions verified? Was error handling reviewed for potential information leaks? These checklists ensure that nothing is missed and that testing efforts are consistent.
Penetration test reports and audit findings also help measure test coverage. These reports reveal which parts of the environment were assessed, which attack paths were explored, and what results were obtained. By analyzing these documents, you can identify coverage gaps and areas that need more attention.
Measurement must be ongoing. Organizations should produce regular coverage reports that document what has been tested, what has not, and what the results were. These reports promote transparency, accountability, and informed decision-making. They also provide a basis for tracking improvements over time.
For more cyber related content and books, please check out cyber author dot me. Also, there are other podcasts on Cybersecurity and more at Bare Metal Cyber dot com.
Now let us move on to how organizations can implement effective test coverage and measurement practices. The first step is documentation. Define the scope of your testing program and clearly describe your coverage objectives. Explain what is in scope, what coverage looks like for each asset, and how success will be measured. This documentation should also describe the tools, techniques, and frequency of testing.
Next, schedule regular security assessments across all critical environments. These assessments might include vulnerability scans, penetration tests, configuration reviews, or compliance audits. The key is to ensure that no critical system goes untested for too long. For example, public-facing systems might be tested monthly, while internal applications might be tested quarterly.
Tools can help track coverage automatically. Automated testing tools can report which systems were scanned, what tests were run, and what results were returned. Manual testing results can be logged in test tracking systems to provide a full picture of coverage. Combining automated tracking with manual verification ensures that nothing is missed and that test results are accurate and meaningful.
Coverage criteria should be reviewed regularly. As new threats emerge, as systems are updated, and as the business evolves, your testing strategy must adapt. Review your criteria and update them as needed. This ensures that your coverage remains aligned with current risks and priorities.
Training is also important. Everyone involved in testing—analysts, developers, administrators—needs to understand how coverage is measured and why it matters. They should know how to define test scenarios, use tracking tools, and interpret measurement data. Well-trained staff make better decisions and produce more reliable test results.
Security controls support test coverage and measurement by enabling visibility, security, and traceability. Logging and monitoring tools help detect anomalies or untested areas by revealing gaps in security data. Access control mechanisms protect testing records and ensure that only authorized personnel can modify them. Regular audits validate that tests meet defined objectives and that coverage levels are sufficient.
Analytics tools can correlate coverage data with incident reports, vulnerability scans, and threat intelligence. For example, if a certain system is frequently targeted by attackers but is rarely tested, that is a red flag. Advanced analytics reveal these insights and guide smarter testing decisions.
Organizations must also store and manage test records securely. These records are often reviewed during audits and must be protected against tampering, deletion, or unauthorized access. Backup systems should ensure that measurement data is preserved and recoverable in case of an incident.
Continuous improvement is essential. Review your test coverage strategies on a regular basis, using input from past incidents, new regulations, and advances in technology. Conduct post-test reviews to identify what worked well and what could be improved. Use this feedback to refine your practices and raise the overall quality of testing.
Cross-functional collaboration is a major factor in success. Developers, testers, security teams, and business leaders must all be involved in defining, executing, and evaluating test coverage. When everyone understands the goals and shares responsibility, testing becomes more effective and more aligned with organizational priorities.
Ongoing training keeps everyone aligned. Staff must be educated not only in testing tools but also in security principles and compliance requirements. Training helps maintain awareness and ensures that your test coverage program evolves with the threat landscape.
Thank you for joining the CISSP Prepcast by Bare Metal Cyber. Visit baremetalcyber.com for additional episodes, comprehensive CISSP study resources, and personalized certification support. Deepen your understanding of Test Coverage and Measurement, and we'll consistently support your journey toward CISSP certification success.