What is the best way to assess aggregate risk derived from a chain of linked system vulnerabilities?

The best way to assess aggregate risk derived from a chain of linked system vulnerabilities is through penetration tests. Penetration testing simulates real-world attacks on a system to identify vulnerabilities and understand how they can be exploited in conjunction. This method allows security professionals to measure not only individual vulnerabilities but also how they interact and contribute to the overall risk of a system being compromised.

Unlike vulnerability scans, which primarily identify known vulnerabilities without context, penetration tests provide deeper insights by testing the interconnectedness of vulnerabilities and the potential paths an attacker might take. This holistic view is essential for understanding aggregate risk because it reveals how various vulnerabilities can be exploited together, leading to a more significant impact if left unaddressed.

Security audits and code reviews focus more on compliance and best practices rather than the practical exploitation of vulnerabilities in a linked manner. While they are important for a robust security program, they do not provide the same level of insight into the operational risks associated with the specific interactions between multiple vulnerabilities. Thus, penetration testing stands out as the most effective method for assessing aggregate risk in this context.