Information leaks and data breaches

Information leaks and data breaches make it easier for cybercriminals to access your accounts.

In recent years, millions of Australians have been affected by major data breaches, such as with Optus and Medibank.

Information leaks aren’t only caused by major data breaches. They're also caused by phishing attacks and scammers tricking people into providing their personal information.

Here we explain everything you need to know, including the practical steps you should take if your information is leaked.

What is an information leak?

An information leak is when your private information is shared online without your permission.

Data breaches are one of the main causes of information leaks. A data breach is when a cybercriminal steals people’s private information from a business or organisation, such as:

personal information. For example, your name, date of birth and address.
medical records. For example, your Medicare history.
financial information. For example, your bank account login information.
account details. For example, your usernames, passwords and email addresses.

Cybercriminals want this information because they can make money trading or selling it online.

Why are information leaks bad?

If your information is leaked, your online accounts could be easily accessed by cybercriminals. Once cybercriminals have your information, they could:

steal your money
steal your identity
target you in a scam
pretend to be you online
open accounts in your name
access your other accounts that use the same account details
send spam or phishing emails from your email address.

Top tip

Cybercriminals know that many of us use the same username and password for our online accounts. They may try to use the account details they’ve stolen from one of your accounts to log into your other accounts. The best way to prevent this from happening is to use a different password for every online account and turn on multi-factor authentication (MFA) where available.

Simple steps to protect yourself after an information leak

It’s not always possible to prevent information leaks. They’re sometimes out of our control, such as when there’s been a data breach.

The good news is that you can minimise further harm in a few simple steps. We’ve outlined them below – follow the ones relevant to your situation.

If your identity is affected by a cyber incident, you may need to replace or secure your government-issued identity documents. Here’s how:
Medicare card number
If you’ve been notified that your Medicare card number has been exposed in a data breach, you can get a free replacement Medicare card using either:
- your Medicare online account through myGov
- the Express Plus Medicare mobile app.
If you’re worried about the security of your Medicare or myGov accounts, contact the Services Australia Scams and Identity Theft Helpdesk on 1800 941 126 (available 8am to 5pm AEDT Monday to Friday).
It’s important to know that your Medicare card number alone cannot be used to access your Medicare details or your Medicare account.
Centrelink Customer Reference Number
If your Centrelink customer reference number (CRN) has been exposed by a data breach, you don’t need to get a replacement concession or health care card. This is because that card or your CRN alone can’t be used as a proof of identity. 
If you’re worried about your CRN being exposed, you can ask Services Australia to add more authentication measures to protect your Centrelink information.
For any concerns about the security of your Centrelink or myGov accounts, contact the Services Australia Scams and Identity Theft Helpdesk on 1800 941 126 (available 8am to 5pm AEDT Monday to Friday).
Tax file number
Visit the Australian Taxation Office’s (ATO) website for information about lost or stolen tax file numbers (TFNS).
Contact the ATO’s Client Identity Support Centre on 1800 467 033 from 8am to 6pm, Monday to Friday, if you have any concerns.
Driver licence
If your Victorian driver licence details have been stolen as part of a cyber incident, you can apply for a replacement licence. The easiest way to do this is online.
Visit VicRoads’ website for more information.
Contact your bank
If you’re involved in a cyber incident, contact your bank immediately to let them know.
You can ask them to put extra safeguards on your accounts. Check if you’ll be charged for this service and if it will impact how you usually access your accounts.
If you’ve lost money, don’t accept offers from third parties to help you get it back. This is a common way scammers try to steal more money from you. 
Check your credit report
Your credit report keeps track of your financial history. It may include details of your bill payments, use of credit or any debts you have.
Checking your credit report will show you if someone is using your personal details to get loans or credit for big purchases, like a car.
You may be able to get one from your bank, or you can request a free credit check from trusted consumer credit reporting agencies. Since different agencies may hold different information, you could have a credit report with more than one agency.
If anything doesn’t look right, act straightaway. Contact your bank or finance company immediately to inform them.
You can also ask the consumer credit reporting agency to temporarily ‘suppress’, ‘freeze’ or ‘ban’ your credit report. This will limit who can see your credit information or take out a loan in your name.
- Want to know more about credit reports and credit scores? Visit Moneysmart’s website.
- Want to know more about how to get a temporary ‘ban’ on your credit report? Visit The Office of the Australian Information Commissioner’s website.
After a cyber incident, your identity, accounts or finances may be affected. Keep an eye out for signs of:
Identity theft
Identity theft is when cybercriminals use your leaked personal information to impersonate you or steal your identity.
Warning signs of identity theft may include:
- your bank statements show spending, deposits or withdrawals you haven’t made
- you stop receiving your regular mail (such as bank statements or utility bills)
- you unexpectedly stop receiving mail altogether
- you receive bills or receipts for things you haven’t bought
- you receive statements for loans or credit cards you haven’t applied for
- you start receiving a government benefit that you haven’t applied for
- you’re refused credit because of a poor credit history due to debts you have not incurred
- you’re contacted by debt collectors.
What do if your identity has been stolen
If someone has taken over your social media accounts
- Contact the service provider's support service for advice on getting your accounts back.
If someone has access to your financial accounts or documents
- Report any documents (like your passport or driver licence) you believe someone else has used without your knowledge.
- Call your bank immediately if you have issues with your credit card or bank accounts.
- Check your bank statements for any transactions you didn’t make.
- Cancel any purchases you didn’t authorise.
- Contact the service provider for your online accounts (like your bank or email provider) and explain what’s happened.
- Change the passwords for any online accounts you think might be at risk.
- Get a free credit check.
Account compromise
Common signs that someone may have accessed your email account include:
- trouble accessing your email as the password you usually use is incorrect
- strange emails in your sent folder
- unexpected password reset notifications
- sign-ins from unusual locations, IP addresses, devices and/or browsers.
What do if your account has been compromised
Follow these steps if you believe your account has been compromised:
- Reset the account password, if possible. Make sure to create a strong password and add MFA if available.
- Cancel any cards linked to that account.
- Contact the service's support desk for advice on getting your account back.
- Visit our Get support page.

How do I find out if my information has been leaked?

If you want to find out if you’ve been impacted by an information leak, you can:

Businesses and organisations may contact you directly to let you know if they’ve been affected by an information leak. They may tell you what information has been affected and what you can do now.
You can also contact the organisation directly or visit their website to look for any official information about the leak.
It’s also a good idea to check the news for reports of major information leaks and data breaches.

Safety & emergencies

Updated 1 May 2024