What assessment tool is designed to improve application security on EC2 instances?

Amazon Inspector is the appropriate assessment tool for improving application security on EC2 instances. It is specifically designed to carry out automated security assessments of applications running on Amazon EC2. By evaluating the security state of EC2 instances, Amazon Inspector identifies vulnerabilities and deviations from best practices, allowing users to take necessary actions to remediate potential security issues. This helps in maintaining a secure environment for applications, ultimately enhancing their security posture.

In contrast, AWS Shield is a managed DDoS protection service that safeguards applications from distributed denial of service attacks, rather than focusing specifically on application security assessments. Amazon GuardDuty is a threat detection service that continuously monitors for malicious activity and unauthorized behavior, but it does not perform direct security assessments on EC2 instances. AWS WAF (Web Application Firewall) protects web applications by filtering and monitoring HTTP traffic, but it does not assess vulnerabilities in EC2 instances themselves. Hence, Amazon Inspector is uniquely positioned to provide the detailed security assessments necessary for securing applications running on EC2.