Stop MFA Fatigue Attacks: Simple Steps to Protect Your Business

What is an MFA fatigue attack?

• Attackers steal or guess a password
• They spam push notifications to the user’s authenticator app
• Under pressure or confusion, the user accepts one request, granting access

Why your business is at risk

• Reused or weak passwords on Microsoft 365 or other cloud apps
• Staff working on the go and approving prompts without context
• Lack of conditional access rules or sign-in risk policies

How to defend fast

1. Switch to number matching or passkeys
   • Enforce number matching in Microsoft Authenticator
   • Prefer phishing-resistant methods: FIDO2 security keys or platform passkeys
2. Reduce prompts
   • Require MFA only from new devices, new locations, or risky sign-ins
   • Enable sign-in risk policies if you have Microsoft Entra P2
3. Lock down legacy and unattended access
   • Disable legacy authentication protocols
   • Use app-enforced restrictions and device compliance
4. Monitor and alert
   • Turn on security defaults at minimum
   • Configure alerting for multiple denied MFA prompts and impossible travel
5. Train your team
   • Teach staff: if you didn’t try to sign in, always tap Deny and report it

Quick checklist

• [ ]  Number matching or passkeys enforced
• [ ]  Legacy auth blocked
• [ ]  Conditional Access in place
• [ ]  Alerts for repeated MFA prompts
• [ ]  Staff training completed

What Clyk can do

• Review your current MFA setup
• Implement Conditional Access and risk-based controls
• Roll out phishing-resistant authentication company-wide

Need help hardening MFA? Book a quick review and we’ll lock it down.