Zoom Rare Audio Devices Detection

This rule detects rare audio devices used in Zoom meetings by analyzing Zoom logs. It specifically looks for speaker devices that are not commonly observed (e.g., not iPhone, FaceTime, AirPods, or MacBook built-in devices). The intent is to identify unusual device usage that could be indicative of Remote Employment Fraud (REF), where actors might use atypical setups. The rule uses a 'rare' command to find the top 50 least frequent speaker devices after filtering out common ones.