EMAIL · DATA BREACHES · ACCESS
How to check if your email address has been breached: the complete guide
Breaches affecting online shops, social networks or collaboration tools can expose user information. Reusing a password across these services and a work mailbox increases the possible consequences of a leak.
Learn how to check whether an email address has been breached or appears in a known leak, interpret the result and secure affected accounts without sharing your secrets.
1. How does your data become exposed?
A breach at a third-party service
Signing up to a forum, online shop or collaboration platform associates your address with an account. A breach may expose information such as email addresses, contact details and sometimes passwords or password hashes. The data involved depends on the incident. It may circulate in private or public collections without necessarily appearing on the dark web.
Credential stuffing and password reuse
Attackers may automatically test stolen email/password combinations on other services. Reusing passwords increases the risk that an external breach affects personal or work accounts. An address alone does not grant access to your mailbox; the risk depends on the exposed data and account protections.
Targeted phishing
Knowing which services you use, your phone number or other details can make a deceptive message more convincing. An email quoting accurate information about you is not necessarily legitimate. Verify the request independently before sharing information or approving an action.
2. Use a breach checker without sharing your credentials
A compromised email checker does not need your password, MFA code or recovery key. Only check an address you are authorised to check.
For its LeakCheck lookup, SecurCheck sends the first 24 characters of the address’s SHA-256 hash rather than the complete address. Reducing transmitted data does not guarantee absolute anonymity. Results depend on the information held by the registry.
Referenced breach sources
The report lists sources associated with your address in the queried registry. It is not an exhaustive search of the internet or dark web. A collection may combine multiple incidents, and private, recent or unindexed breaches may be missing.
Available dates
Reported dates provide context but may be incomplete or approximate. They do not, on their own, prove that your current password is exposed. Compare them with your password changes and official notices from the affected service.
Data categories
Depending on available information, the report shows categories such as email addresses, passwords or phone numbers. These describe data reported by the source; they may not establish exactly which fields relate to you in each incident. No password is required for the check.
Anticipate the impact of breaches on work accounts
A leak at an external service can become a business risk when passwords are reused. SecurCheck Business helps your teams look for known exposure, understand the signals and pass useful information to IT.
This on-demand check complements identity management and awareness efforts. It is neither exhaustive dark web monitoring nor a complete audit of your organisation’s access.
Explore the Business offer and strengthen security habits3. What should you do if your address appears in a breach?
Review the reported services and data, then adapt your response. An exposed address calls for particular vigilance against phishing; possible password exposure calls for securing the affected accounts.
Secure the affected accounts
Go directly to the service’s official website or app. If a password may have been exposed, replace it with a long, unique password, ideally generated and stored in a password manager. Do not follow a link in an unverified alert.
Eliminate password reuse
Also change that password on every other service where you used it, prioritising your mailbox and work accounts. Choose a different secret for each account rather than a predictable variation.
Strengthen authentication
Enable MFA and prefer phishing-resistant methods such as passkeys or security keys where supported. MFA reduces risk, but conventional codes and push notifications do not protect against every attack, including session theft. Never approve a sign-in request you did not initiate.
Review access and report anomalies
Review recent sign-ins, devices, recovery methods, authorised apps and mailbox forwarding rules. If you find an unfamiliar session or suspicious activity, use available sign-out options and alert IT for a work account. A password change does not necessarily close every session.
Make account security a regular habit
Unique passwords, strong authentication and access reviews limit the consequences of a breach. Periodic checks for known exposure help prioritise action without guaranteeing detection of every incident. Checking a suspicious incoming email is a different task: it examines the message, not whether your address appears in a breach.
Learn to analyse a suspicious message