Quick answer
If you suspect a data breach, first check trusted sources like Have I Been Pwned or company notifications. Then immediately change passwords on affected accounts, enable two-factor authentication, and monitor for suspicious activity. Do not ignore the problem because attackers can misuse data months later.
How to recognize the problem
- You receive suspicious emails containing your personal data
- You notice unknown logins to your accounts
- Friends ask you why you are sending them strange messages
- You find your data on the dark web or forums
- You receive a notification from a company about a data breach
Most common causes
Breaches on services
Large services like social networks or email providers are often targeted by hackers, and user data can be stolen.
Phishing attacks
Attackers can get your data if you clicked on a fake link and entered it on a fraudulent site.
Weak passwords
If you use the same password in multiple places, a breach from one service can compromise all other accounts.
Malicious software
Malware on your computer can steal saved passwords and data from your browser.
Step-by-step fix
- 1
Check if your data has been breached
Visit trusted sites like
haveibeenpwned.comand enter your email address. Also, check notifications from companies you may have forgotten about. If you get a positive result, note which service was affected and what information may have been stolen. - 2
Change passwords on affected accounts
Immediately change the password on every account that was part of the breach. Use a unique, strong password for each account. If you use a password manager, update the password in it. Do not reuse old passwords.
- 3
Enable two-factor authentication
Enable 2FA on all important accounts (email, bank, social networks). This can be an SMS code, an authentication app, or a hardware key. This makes it much harder for attackers to access even if they know the password.
- 4
Check active sessions and connected apps
In your account settings, review the list of devices and sessions. Log out of all unknown devices. Also, remove access for apps you do not use or that look suspicious.
- 5
Monitor for suspicious activity
In the coming weeks, pay attention to unusual logins, password changes, or received messages. If you notice anything suspicious, react immediately. You can also set up login notifications if the service allows it.
- 6
Notify contacts if necessary
If your email address or contact list was leaked, warn friends and colleagues to ignore suspicious messages that appear to come from you. This prevents further spread of phishing attacks.
- 7
Consider changing your email address
If your primary email address is compromised and you receive a lot of spam, consider creating a new address. Gradually transition to the new address and inform important contacts. Keep the old address for a while for transition, but do not use it for sensitive accounts.
- 8
Check financial data
If credit card or bank account data was leaked, immediately notify your bank and monitor transactions. You can request a new card and set up alerts on your account.
What if the check shows nothing but you suspect a breach?
Sometimes a breach is not publicly disclosed or the data is sold on the dark web. In that case, pay attention to symptoms such as unexpected calls, mail, or messages with your data. You can hire a security professional to search the dark web, but be cautious with services that promise miracles. Regularly check your accounts and use unique passwords. If you notice any suspicious activity, report it to the authorities immediately. Do not forget to update software and be careful about sharing personal information online.
How to prevent it
- Use unique and strong passwords for each account
- Enable two-factor authentication wherever possible
- Regularly check if your data has been breached
- Do not click on suspicious links and do not share personal data carelessly
When to call a professional
If you notice that your identity has been stolen, that unauthorized accounts have been opened, or that you have financial losses, contact IT experts or lawyers specializing in cybersecurity. Also, if you are not sure how to protect business accounts, consult IT support.
IT infrastructure maintenance · Servers, networks, backup, security and helpdeskFAQ
How often should you check if your data has been breached?
It is recommended to check every few months, and immediately after you hear about a major data breach. You can sign up for notifications through services like Have I Been Pwned.
Is changing the password enough?
Changing the password is the first step, but it is not enough. Enable two-factor authentication, check active sessions, and monitor for suspicious activity. If financial data was leaked, notify your bank.
What if my passport or ID card data was leaked?
Immediately notify the police and relevant institutions. You can request new documents. Monitor whether someone tries to misuse your identity, for example to open accounts or take out loans.