After a breach, you can secure
- Make compromised passwords or sessions unusable.
- Enable additional protections on affected accounts.
- Keep evidence and report fraudulent use.
Understand the exposure, prioritise your response
Data breach : check what was exposed and how to protect yourself
Email, password, phone number, IBAN or identity document: the right response depends on the data exposed. Identify the breach, secure affected accounts and watch for unusual activity.
The first minutes matter
Your data was breached? Start with these four steps
Focus your response. First secure access that could be used immediately, then organise monitoring and further action.
- 01 · Verify
Confirm the breach through a reliable source
Read the affected service's official notice and check the address used. Avoid links in alarming messages: open the website or app directly.
- 02 · Secure
Change the affected password
Choose a unique password. If you reused it elsewhere, change it on those accounts too, starting with your email and sensitive services.
- 03 · Lock down
Sign out other sessions and enable 2FA
Revoke devices or connections you do not recognise, then enable two-factor authentication using an app or security key where possible.
- 04 · Monitor
Watch for unusual activity
Monitor sign-ins, resets, messages and transactions. Be especially wary of calls or emails that use accurate information about you.
Not all exposed data carries the same risk
The size of a breach does not tell the whole story. One sensitive detail may need a faster response than a long list of already public information.
- Common risk
Email, phone number or address
Phishing, text scams, targeted spam and fraudulent calls become more credible when an attacker already knows part of your identity.
Stay alert and strengthen your account filters. - High priority
Password or security answer
Reused credentials can unlock other accounts through credential stuffing. An old security answer can also help someone take over an account.
Immediately change affected or reused credentials. - Closer monitoring
IBAN or payment details
This information can support fraud, bank impersonation or an attempted direct debit. If complete card details are exposed, contact your bank promptly.
Contact your bank and monitor transactions. - Potentially severe impact
Identity, health or official documents
An identity document, administrative number or health information can enable identity theft or cause lasting, sensitive harm.
Keep evidence and follow the appropriate official process.
Understand the scenario
What a breach actually lets an attacker do
One isolated detail is not always enough to act. Risk increases when it is reused, combined with other sources or turned into a convincing pretext.
Try your credentials elsewhere
Automated tools test email and password combinations on other services. This is why every account needs a unique password.
Write a convincing message
Real information stolen in a breach can make a fake email, text or call much more convincing. Stay alert.
Enrich your profile
Breached data can be combined with the public web, social networks or broker databases to fill out your profile.
Impersonate a familiar contact
An attacker may pose as a bank, phone provider or service you use to obtain a code, payment or more information.
Securing data is not the same as removing it
Can breached data be deleted?
A database that has already been copied or shared usually cannot be erased everywhere. You can still disable compromised access and act against organisations, sites or brokers that hold or publish your data.
Elsewhere online, you can request removal
- Request erasure from the organisation still holding the data.
- Have information removed from a website or broker.
- Track GDPR requests and confirmations actually received.
With a Data Knight scan
How to check known breaches affecting you
Data Knight makes Have I Been Pwned results easier to read: see incidents linked to your contact details, the types of data affected and actions to prioritise.
- 01
Enter your email or phone number
The scan does not need your password to look for a match in known breaches.
- 02
Data Knight checks Have I Been Pwned
The search covers incidents recorded and documented by this international reference database.
- 03
See your results in context
Your report identifies the affected service, the known breach date and the categories of exposed data to help you prioritise.
Check and learn more
Content reviewed against official resources and the documentation of the source used by the scan.
Frequently asked questions
See all FAQsUseful answers after a data breach
How can I find out whether my personal data has leaked?
First check official notifications from services you use and unusual activity on your accounts. You can also check your email address or phone number in a recognised database such as Have I Been Pwned. The Data Knight scan brings known matches and the categories of exposed data together in one report.
What should I do if my password appears in a breach?
Change the password for the affected account immediately. If you reused it, change it on every other account using the same combination, starting with your email and financial services. Sign out unfamiliar sessions and enable two-factor authentication.
Do I have to change all my passwords?
Not necessarily. Prioritise the affected service and every account using the same password or a close variation. A password manager can then help you create a strong, unique password for each account.
Can leaked data be permanently deleted?
Not everywhere once a database has been copied or shared. You can still make compromised credentials unusable, secure your accounts and request deletion of data still held or published by an organisation, website or broker. A removal request cannot guarantee that every copy from a breach disappears.
Does a negative result mean my data is safe?
No. It only means that no match was found in the known breaches checked at the time of the search. A breach may not yet have been discovered, may not be public or may be added to the database later.
What should I do if my IBAN or ID document was exposed?
For an IBAN or payment details, contact your bank and monitor unusual transactions. For an ID document, keep evidence, watch for signs of identity theft and follow the appropriate official reporting process if fraudulent use appears. Do not send another document to an unverified contact.
Is Have I Been Pwned reliable?
Have I Been Pwned is an internationally recognised database of documented breaches and the categories of data affected. It cannot know about every breach, so treat a result as a useful signal rather than an absolute guarantee of security.
Does Data Knight store my passwords?
No. The Data Knight breach scan does not need your password. It uses the contact details you provide, such as your email address or phone number, to look for matches in recorded incidents and display useful information in your report.