This rule detects anomalous behavior that indicates suspicious sign-in activity occurring across multiple tenants from distinct geographic locations using the same browser. Such behavior can indicate potential security threats like account compromises or coordinated attacks targeting users' credentials. It leverages the Azure risk detection service to identify these risky events based on predefined criteria. The key indicator for the detection is the 'riskEventType' set to 'suspiciousBrowser'. Given the nature of this event, a high level of scrutiny is warranted for flagged sessions, while always contextualizing with other sign-in attempts. False positives may arise; thus, further investigation into user activity is crucial to ensure actions taken are appropriate to the threat level.