Credential stuffing

How it works

• Attackers buy lists of leaked email and password pairs.
• Software tries each pair on Microsoft 365, banks and supplier portals at high speed.
• Any reused password that matches gets the attacker in, with no hacking needed.
• Unique passwords and MFA break the attack.

What can go wrong (example scenario)

A four-person interior design firm reused one password across their email, their supplier portals and their online banking. A breach at a furniture retailer leaked it. Within a day their Microsoft 365 account was taken over and used to send “updated invoice” emails to every client.

How WILDCARD handles it

Identity Monitor watches every login and session around the clock and shuts down suspicious activity automatically. Password Manager removes the reuse that makes the attack work.

• A dental office sees a wave of failed logins against staff mailboxes from overseas addresses.
• A law firm gets alerted when a password leaked from a legal publisher's breach is tried against their tenant.
• A retailer's Shopify admin account is probed with credentials from an unrelated breach.

Example scenario: A small clinic's monitoring showed forty login attempts against the office manager's account in ten minutes, all from different countries. Her password was unique and MFA was on, so every attempt failed. The alert still led to a quick review, and an old shared mailbox with a weak password was found and fixed the same day.

A question owners ask

If I have MFA, does credential stuffing still matter?

MFA stops most of it, and a unique password stops the rest. Monitoring matters because a burst of attempts tells you a password is out there and needs changing.