This rule detects instances where user access is blocked by Azure Conditional Access policies, which could indicate potential unauthorized login attempts to valid accounts. When a user attempts to log in, Conditional Access policies evaluate the request and may block it based on specific criteria such as user risk, location, device compliance, or session risk. The specific detection condition for this rule looks for instances where the ResultType for sign-in attempts equals 53003, indicating that access has been denied due to Conditional Access decisions. Monitoring such blocked access attempts is crucial for identifying and mitigating potential credential attacks and enhancing the overall security posture within Azure environments.