For instance, we can upload an attachment we obtained from a potentially malicious email and see what URLs it attempts to communicate with, what additional payloads are downloaded to the endpoint, persistence mechanisms, Indicators of Compromise (IOCs), etc.

Any.Run: https://app.any.run/

 "Analyze a network, file, module, and the registry activity. Interact with the OS directly from a browser. See the feedback from your actions immediately".

Hybrid Analysis: https://www.hybrid-analysis.com/

"This is a free malware analysis service for the community that detects and analyzes unknown threats using a unique Hybrid Analysis technology_."

https://www.joesecurity.org/

"Joe Sandbox empowers analysts with a large spectrum of product features. Among them: Live Interaction, URL Analysis & AI based Phishing Detection, Yara and Sigma rules support, MITRE ATT&CK matrix, AI based malware detection, Mail Monitor, Threat Hunting & Intelligence, Automated User Behavior, Dynamic VBA/JS/JAR instrumentation, Execution Graphs, Localized Internet Anonymization and many more".