Passwords Are Broken: How Passkeys & WebAuthn Fix Authentication in ASP.NET Core and Microsoft 365

Passwords aren’t failing because users are careless—they’re failing because the model is fundamentally outdated. Phishing, credential stuffing and endless resets show how fragile a system is that still depends on humans remembering secrets at internet scale. In this episode, you’ll see why tightening password policies barely moves the needle, how much breaches and resets really cost your organization, and why it’s finally realistic to remove passwords altogether instead of patching them.

We start with the true cost of “just one” stolen credential: how a single compromised Microsoft 365 admin account can lead to Teams data exposure, mailbox abuse and weeks of recovery work—without any zero-day exploit. Then we look at the hidden tax of password resets and rotation policies that burn IT time, frustrate employees and still don’t stop attackers from reusing old patterns. You’ll walk away with a clear picture of why passwords can’t scale to today’s threat landscape, no matter how many special characters you add.

From there, we introduce passkeys and WebAuthn as the realistic alternative, not science fiction. You’ll learn how public‑key cryptography flips the model—private keys stay safely on the device, servers only store public keys, and there’s nothing usable for attackers to steal from your database. We break down what this feels like for users (Face ID, Windows Hello, security keys), how WebAuthn lets browsers and platforms talk the same language, and why phishing pages simply stop working when there’s no password to type.

Finally, we get practical for ASP.NET Core teams and decision‑makers. Developers get a high‑level implementation checklist: where to plug passkeys into existing auth flows, which parts of your app change, and what to watch out for in rollout. Leaders get the adoption view: how to position passkeys as both a security and productivity upgrade, what to measure (reset volume, phishing exposure), and how to decide if you’re the one implementing the change or the one sponsoring it.

WHAT YOU’LL LEARN

• Why passwords keep failing even with stricter policies and better monitoring.
• How passkeys and WebAuthn replace passwords using public‑key cryptography and device‑based authentication.
• What the sign‑in experience looks like with Windows Hello, biometrics and security keys.
• A practical ASP.NET Core checklist for adding passkey support to your existing login flows.
• How to talk about passwordless authentication with business leaders in terms of risk, cost and user experience.

THE CORE INSIGHT

The core insight of this episode is that passwords aren’t a behavior problem, they’re an architecture problem. Once you stop trying to train users into impossible habits and instead move to passkeys and WebAuthn, you remove the single point of failure attackers depend on—without making sign‑in more painful for the people you’re trying to protect.

WHO THIS EPISODE IS FOR

• ASP.NET Core and identity developers implementing secure login flows.
• Security and IAM teams planning passwordless, FIDO2 and WebAuthn projects.
• IT and business leaders who need to cut phishing risk, reset volume and credential management costs.

ABOUT THE AUTHOR / HOST

Mirko Peters is a Microsoft 365, security and identity consultant and host of the M365.FM podcast, helping organizations treat authentication, devices and cloud apps as one integrated operating system instead of scattered login screens. He works with teams running on Microsoft 365, Azure and modern .NET to design passwordless strategies—using passkeys, WebAuthn and strong device identity—so “just one bad password” stops being the root cause of their biggest incidents.

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