Unlocking Vulnerabilities: User Enumeration in Microsoft 365

This chapter explores the preliminary steps attackers take before launching brute-force attacks on user accounts, with a focus on identifying email formats and utilizing tools for user enumeration within Microsoft 365. It highlights the risks associated with these tactics, such as facilitating password spraying and social engineering attacks, while emphasizing the importance of multi-factor authentication and strong security measures. The chapter also discusses the vulnerabilities of SharePoint and related services, urging IT administrators to understand enumeration tactics for better protection against potential breaches.