October is Cybersecurity Awareness Month, a reminder that even the most advanced cloud environments are only as secure as their configurations. If your organization runs on Microsoft 365, your identity plane has become your new perimeter, and misconfigurations are among the most common ways attackers gain a foothold.
The good news? Most of these risks are preventable with clear controls, repeatable checks, and a security mindset that treats identity as the backbone of protection. In this guide, we’ll walk through practical steps to strengthen your Microsoft Entra ID (formerly Azure AD) setup and safeguard the M365 components attackers most often target.In the cloud, an authenticated session often matters more than an IP address or a network segment. If an attacker can log in, register a device, or activate a standing privilege, the rest becomes a permission game. That is why protecting authentication flows, stopping legacy protocols, and keeping privileges just-in-time are the highest value moves you can make.
Treat these as non-negotiables. Each one closes a very common door that attackers use.
Enforce multifactor authentication for everyone, including any service or workload management accounts that are used interactively. Verify your MFA methods are strong and phishing-resistant. Create two break-glass (emergency access) accounts with long, machine-generated passwords, stored separately and securely, exclude these accounts from conditional access policies to facilitate tenant recovery, and configure monitoring and alerting so that your team is notified when those accounts do anything.
Legacy protocols cannot enforce modern MFA and are a favorite for password-spray attacks. Disable legacy auth, including POP/IMAP/ActiveSync, and SMTP Auth tenant-wide via a dedicated conditional access policy. If an app truly needs legacy auth to function, grant it to that one application or account only and monitor it closely.
Attackers can socially engineer phone carriers or intercept messages. Prefer Microsoft Authenticator with number matching, FIDO2 security keys, or platform passkeys. Keep your MFA factors as phishing-resistant as possible.
Device sign-in prompts are a popular lure in phishing campaigns. Restrict who can register or join devices, require devices to be compliant or hybrid joined via CA before granting access, and use Named Locations for network restrictions where appropriate. Additionally, disable the OAuth 2.0 device authorization grant (device code) flow unless you have a known dependency, as it is routinely abused for phishing.
Forwarding rules that send mail outside the tenant are a quiet data exfiltration path. Block external auto-forwarding in the Outbound spam filter policy. Review existing rules in user mailboxes to catch any that slipped through.
Permanent privileged role assignments, like global admin, are an unnecessary risk. Move privileged roles to PIM so access is activated only when needed, require MFA and approval, capture business justification for activating the role, and expire the activation automatically. If you do not separate admin and user accounts, PIM becomes even more important. Remember to periodically review privileged roles and assignments.
Enable the Unified Audit Log and Entra ID sign-in/audit logs. Send them to a SIEM or Defender. Make sure you can answer these three questions quickly: who authenticated, from where, and to what.
One-off hardening leaves gaps. Adopt a benchmark and work it methodically.
Enforce MFA, create emergency accounts, disable legacy auth, and block external forwarding.
Refine conditional access policies, allowed auth methods, and device registration controls.
Roll out PIM for global admin and other high-impact roles.
Enable and route logs, set core alerts, and document your baseline exceptions.
Most identity breaches in M365 are not zero-day stories. They start with legacy protocols that should have been off, weak MFA that should have been stronger, privileges that should have been temporary, and logging that should have been enabled. Close those gaps first. Work from an industry benchmark, not an ad-hoc checklist in someone’s head. Keep privileges just-in-time, keep your methods phishing resistant, and keep your logs flowing to a place you actually review.
Do the simple things thoroughly, and you will remove a surprising amount of risk in a very short time.
If you’re ready to take your security posture seriously, contact our team to start your next penetration test with confidence.