I Checked 10 of My Old Passwords Against Breach Databases. Here's What I Found.

It started with a weird email. Someone had tried to log into my old Dropbox account from a device in Romania. I hadn't touched that account in three years, but I still had stuff in it — old tax documents, some freelance contracts, a folder embarrassingly titled "Important Misc." I changed the password immediately, told myself I'd be more careful, and forgot about it within a week.

That was two years ago. Last month, I finally did what I'd been putting off: I actually sat down and audited my old passwords. Not just changed them, but checked whether they'd already been exposed in data breaches I didn't even know about. What I found was uncomfortable enough that I'm writing this down.

Why I'd Never Done This Before (And Why That Was Stupid)

I think I had this vague idea that if something bad had happened with my accounts, I'd know about it. I'd get an email, or I'd see a suspicious charge, or my account would just stop working. That's not how it works, and I knew that intellectually, but knowing something and acting on it are different things.

The reality is that stolen credentials often sit on underground markets for months or years before anyone uses them. Sometimes they're sold in bulk to spammers. Sometimes they're tested quietly against financial accounts with automated tools. The victim frequently never finds out — at least not until something concrete and damaging happens.

I use a browser password manager, which I'd assumed was basically fine. But I'd been using it inconsistently, and I had this trail of old accounts from the early 2010s — forums, smaller services, a handful of shopping sites — where I'd just reused variants of the same two or three passwords. I knew this. I just hadn't dealt with it.

The Audit: What I Actually Did

I picked ten accounts. Not randomly — I deliberately chose a mix: some that felt sensitive (my old university email, a health insurance portal I'd registered with years ago, an Amazon account I still actively use), and some that seemed low-stakes (a photography forum, a recipe aggregator, the account from a now-defunct file-sharing site).

For each one, I first checked Have I Been Pwned (haveibeenpwned.com). If you haven't used this, it's a free service run by security researcher Troy Hunt that aggregates data from known breach dumps. You type in your email address and it tells you which breaches included that address. It doesn't store your actual password — it just flags which datasets your email appeared in.

My email showed up in seven breaches. Seven. LinkedIn (the massive 2012 one — 117 million accounts), Adobe, Dropbox, a breach from a shopping site I'd completely forgotten I had an account with, and three others I had to look up to even recognize.

Then I went one step further: I checked the actual passwords using HIBP's password checker. This tool uses a method called k-anonymity — you don't send your full password to the server, just the first five characters of its SHA-1 hash. The service returns all hashes that start with those characters, and your browser checks locally whether yours is in the list. It's cleverly designed so even the service itself never learns what you typed.

My old "secure" password — the one I'd considered clever because I'd swapped letters for numbers and added an exclamation point — had been seen 847 times in breach data. That number hit differently than I expected.

What the Results Actually Looked Like

Here's the breakdown, and I'm being honest even where it's embarrassing:

3 accounts were using a password I'd thought was my "strong" one. It wasn't. HIBP had seen it over 800 times. These included my old university login (which still technically worked for library access) and one account connected to a recurring subscription I'd forgotten to cancel.

4 accounts were using some variation of the same base password with a different number at the end. Classic pattern-based "security" that any halfway decent cracking tool would defeat in seconds. All four emails had appeared in at least one breach.

2 accounts had unique passwords I'd generated at some point and stored in my password manager. These were fine — neither password appeared in breach data, and only one of the email addresses was in a breach (the LinkedIn one, which everyone was in).

1 account — the defunct file-sharing site — had my old "default" password, and that email and password combination appeared in a credential stuffing list. Meaning someone had specifically packaged that email + password together to try across other sites.

That last one scared me the most. Because I'd used that same password on three other services a decade ago. I couldn't even remember all of them. I spent an evening trying to reconstruct what sites I'd signed up for between 2009 and 2014, which is its own particular kind of digital archaeology.

The Tools That Actually Helped

Beyond HIBP, I used a few other things worth mentioning:

Bitwarden's built-in breach report — I'd migrated most of my passwords here last year. Bitwarden can check your stored passwords against breach data automatically and flag reused passwords across your vault. It found 11 instances of password reuse I hadn't noticed. It also generates genuinely random passwords (I now use 20-character ones by default) and the free tier covers everything most people need.

Firefox Monitor — Similar to HIBP but integrated into the browser. It sends ongoing alerts if your email appears in new breaches. I set this up for my three main email addresses. It's not perfect, but it means I'm not relying entirely on my own memory to stay on top of this.

A password strength checker I was skeptical of — I tried a few online "rate my password" tools out of curiosity. Some are useless (they rate password length without considering whether the password is in breach lists). The better ones estimate crack time based on realistic attack models. The lesson: length matters more than character substitution tricks. "correcthorsebatterystaple" is more resistant than "P@ssw0rd!" not because it's clever but because it's long.

What I Changed and How Long It Actually Took

Fixing this took one focused evening — maybe three hours total. That sounds like a lot, but I'd been putting it off for two years. Here's what I did:

I went through every compromised account and reset the password to something generated by Bitwarden. I didn't try to come up with them myself — the whole point is to use something I couldn't possibly remember or guess, stored safely. For the accounts I could no longer access (one had been deleted, one required a phone number I no longer owned), I went through account recovery or just accepted the loss.

I enabled two-factor authentication on everything that offered it. This should have been the first step years ago. It doesn't protect you from having your password stolen, but it does mean a stolen password alone isn't enough to get into your account.

For the credential stuffing list hit — the one where my email and password were packaged together — I specifically checked every account where I might have used that combination and changed all of them. Then I set up a Google alert for my email address + "database" and "leak" just as a crude early warning system.

The Uncomfortable Truth This Exercise Left Me With

The thing that stayed with me wasn't any single breach. It was how long I'd been operating under a comfortable illusion of security without anything bad visibly happening. The credentials were out there. They'd been out there for years. I just hadn't been paying attention.

I'm not a paranoid person about this stuff, and I don't think everyone needs to be. But the bar for basic digital hygiene is genuinely low: a free password manager, a free breach-checking service, and an afternoon. The reason most people don't do it isn't that it's hard — it's that it never feels urgent until something actually goes wrong.

My Dropbox login from Romania was a near-miss. The credential stuffing match was a real exposure I'd just been lucky about. I got away with it. Not everyone does.

If your email address has been in your inbox for more than five years, go check it on HIBP right now. Just see. The results might be boring and fine. Or they might be the thing that finally makes you spend an evening fixing what you've been putting off.

Three hours. That's all it took to undo a decade of lazy habits. I wish I'd done it sooner.