How to check if your account has been leaked

Security Knowledge

Why the account is leaked

If you register for many services, there is a high risk that your account will be leaked. This is unavoidable no matter how careful you are.

This is because the database of the registered service may be compromised and the account may be leaked without your knowledge.

I think many people use the same email address and password for multiple services.

Therefore, if an account is leaked in one service, it is possible to gain unauthorized access to other services using that account, which is a dangerous situation.

A site where you can check if your account has been leaked

You can check if your account has been leaked on a site called FireFox Monitor. This site is operated by Mozilla, which provides the browser FireFox.

It's very easy to use, enter the email address you want to look up in the "Enter email address" form and click "Check for data breaches".

If it has not been leaked, the message "This email address has 0 known data breaches" will be displayed as described above.

If it has been leaked, the name of the leaked service and the contents of the data will be displayed.

You can also check it on the site';-have i been pwned?

This is an English page, but the usage is the same as FireFox Monitor, just enter your email address and click "pwned?".

If the e-mail address is not leaked, "Good news --no pwnage found!" Will be displayed like this.

If it was leaked, Oh no --pwned! Is displayed like this, and as you scroll the screen, the leaked service name and contents are displayed.

Recommended is "'; --have i been pwned?"

Firefox Monitor seems to be provided with data from';-have i been pwned ?, but it doesn't seem to be exactly the same data.

The screen shot above shows the results of an inspection with the same email address, but FireFox Monitor shows 172 data breaches and';-have i been pwned? Shows 194 data breaches found.

I looked it up with several email addresses and found that';-have i been pwned? Was more numerous in each case. Therefore, the data is not currently provided to Firefox Monitor from';-have i been pwned ?, or even if it is provided, there is a time lag and the information in Firefox Monitor may be slightly out of date.

What to do if it was leaked

Investigate using the method described, and if your account information is leaked, log in to the service and change your password immediately. However, this is not enough, and if you are using other services with the same email address and password combination, you will need to change all those passwords.

This is why password reuse is not recommended. If account information is leaked from one service, it will affect other services.
In order to minimize the impact of information leakage, do not reuse passwords as much as possible and set different passwords.

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