Security Awareness Briefing  //  Eriu Technology  //  Defensive Use Only

KEYS TO THE
KINGDOM

One password, every door.

Why reusing passwords hands over everything — and why MFA is the cheapest insurance you'll ever buy.

01 / What it is

Credential stuffing is attackers taking passwords leaked from one site and trying them everywhere else, by the million, automatically. Reuse is what makes it pay. Multi-factor authentication (MFA) is the second lock that holds even when the password's gone.

02 / How it works
1
A site you used gets breached; your email and password leak.
2
The pair joins a list traded among attackers.
3
Bots try it against banks, email and work logins — everywhere.
4
Anywhere you reused it, they're in.

→ Your email is the master key: with it, they reset every other account you own.

What saves you

Three habits do almost all the work:

A password managerOne strong one; it remembers the rest.
Unique per siteA breach stays contained to one place.
MFA everywhereA stolen password isn't enough on its own.
Guard your emailIt resets everything else — protect it hardest.
!
Turn MFA on your email firstIf you do one thing today, switch on multi-factor authentication for your email. It's the master key to every other account you have — lose it and you lose the lot. An app code or a hardware key beats a password alone, every time.
03 / Why it's dangerous
  • Reuse turns one breach into many — one leak unlocks every reused account.
  • Strength doesn't help if the whole password has leaked.
  • Your email is the master key — it resets everything else.
  • Bots do it at scale — millions of tries, no effort.
04 / How you stop it
  • Use a password manager so every site gets a unique one.
  • Never reuse across anything that matters.
  • Turn on MFA everywhere, your email above all.
  • Prefer an app or hardware key over SMS codes where you can.
  • Check haveibeenpwned.com to see what's already leaked.
One password · Every door
An Eriu Technology security briefing  ·  Awareness & defence only