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    Passkeys & Phishing-Resistant MFA

    Melissa CollettFebruary 26, 2026

    If you already enabled Multi-Factor Authentication (MFA), congratulations—you’ve moved from “front door wide open” to “front door locked.”

    Unfortunately, attackers noticed… and now they’re ringing the doorbell a lot.

    Modern phishing campaigns don’t just steal passwords—they try to bypass or abuse MFA with tricks like:

    • MFA prompt spam (“push bombing”) — hoping someone hits Approve just to make the buzzing stop
    • Phishing kits that proxy logins in real time — stealing session tokens
    • SIM swaps / SMS interception — because SMS is basically “security by postcard”

    The next step for many businesses is phishing-resistant MFA and passkeys.

    What “Phishing-Resistant MFA” Actually Means

    Phishing-resistant MFA is designed so that even if a user is tricked into visiting a fake login page, the attacker can’t replay the authentication and get in.

    The best-known options include:

    • FIDO2 / WebAuthn security keys (USB/NFC keys)
    • Platform authenticators (Windows Hello, Touch ID, etc.) using passkey-style credentials

    Think of it like this:

    • SMS codes: “Tell me the secret number I texted you.”
    • Push approvals: “Tap the button if you meant to sign in.”
    • Passkeys / FIDO: “Prove you have the right key for this exact website.”

    Attackers hate that last one. (And we love to see it.)

    Passkeys: The “No More Passwords” Upgrade (Without the Chaos)

    Passkeys are a modern sign-in method built on public‑key cryptography. In plain English:

    • There’s no password to steal.
    • The “secret” stays on your device (or secure provider).
    • Logging in usually looks like Face ID / fingerprint / PIN.

    If your users can unlock their phones, they can use passkeys.
    Yes, that means Karen from Accounting can be more secure than a 12‑character password with three exclamation points.

    Why MSP Customers Should Care (Right Now)

    Because identity is still the easiest entry point.

    When a threat actor gets access to email or a cloud identity, the playbook is depressingly predictable:

    • Invoices and payment redirects (BEC)
    • Mailbox rules and data theft
    • Lateral movement into SharePoint / Teams / file sync
    • “Just one admin account” turning into a very bad week

    Phishing-resistant MFA and passkeys raise the cost for attackers dramatically—often enough that they move on to someone easier.

    A Practical Rollout Plan That Won’t Cause a Ticket Avalanche

    Here’s the “do it like an MSP” approach—secure first, then scale.

    1) Start with admins and high-risk accounts

    • Global admins, billing admins, anyone with VPN/RMM access
    • Require phishing-resistant methods first (security keys / Windows Hello/passkey-capable flows)

    2) Reduce the “Approve” button problem

    If you use push MFA today, tighten it up:

    • Turn on number matching (when available)
    • Disable “remember MFA forever” where it’s risky
    • Educate users: If you didn’t start the login, don’t approve it.
      (MFA prompts should be treated like unexpected “Are you awake?” texts at 2am.)

    3) Introduce passkeys in phases

    • Pilot with a small group (IT + a few power users)
    • Validate device readiness (Windows Hello, managed mobile devices, supported browsers)
    • Document a simple “how to enroll” flow and include it in onboarding

    4) Get account recovery right (seriously)

    Passkeys are great—until someone loses a phone and their patience.

    • Confirm recovery options for each user (backup methods, helpdesk verification steps)
    • Use strong identity proofing for resets
    • Log and alert on recovery events

    5) Measure and improve

    Track:

    • MFA challenges by method
    • “Denied push” events
    • Account lockouts and recovery requests
    • Any accounts still using SMS (these are your “please phish me” accounts)

    The Bottom Line

    Traditional MFA is still far better than passwords alone—but phishing-resistant MFA and passkeys are where identity security is heading.

    At Collett Systems, we help MSP customers:

    • choose the right authentication methods,
    • roll them out without breaking workflows,
    • and reduce the real-world risk of account takeover.

    If you want a plan tailored to your environment (Microsoft 365, line-of-business apps, VPN/RMM, and compliance needs), contact us.