Which tools should an analyst use to analyze a suspicious email attachment?

The most appropriate tool for analyzing a suspicious email attachment in this context is Cuckoo Sandbox. This tool provides a dynamic analysis environment where attachments can be executed in a controlled setting. It observes their behavior and interactions with the system, helping analysts identify any malicious activity, such as data exfiltration or unauthorized access attempts, without risking harm to the actual network.

Network Access Control (NAC) is primarily used for enforcing security policies on devices that connect to a network and does not specifically analyze email attachments. Domain-based Message Authentication, Reporting, and Conformance (DMARC) helps prevent email spoofing and improves email deliverability but does not analyze attachments. Security Information and Event Management (SIEM) collects and analyzes log data to provide insights into security incidents but is not designed for the specific analysis of email attachments. Thus, in the scenario of analyzing suspicious email attachments, Cuckoo Sandbox is the correct choice as it provides a dedicated platform for such analysis.