As the lead security engineer for a cloud-based software development company, you are overseeing the integration of several third-party APIs into the company's flagship product. The APIs will enable new features that are critical to the product's success. However, you are aware that integrating external services can introduce new vulnerabilities. What should be the primary focus when evaluating the security aspects of these third-party APIs to ensure they do not compromise the overall security of the cloud-based application?