In the realm of personal and organizational information security, tracking historical data breaches is essential for assessing risk. The website Have I Been Pwned? (HIBP) is a verified, industry-standard tool created by security researcher Troy Hunt that allows individuals and security professionals to check if an email address or username has been part of a publicly known data breach. When a major service (like LinkedIn, Adobe, or MySpace) is compromised, hackers often leak the resulting databases onto the "dark web". HIBP aggregates these leaks into a searchable interface.

For an ethical hacker, HIBP is an invaluable resource during thepassive recognitionphase of an engagement. By checking an organization's employee emails against this database, a tester can identify which staff members have had their credentials exposed in the past. This is critical because many users "recycle" passwords across multiple services. If an employee's password was leaked in a breach of a non-work-related site, an attacker might attempt to use those same credentials to gain access to the corporate network—a technique known as "credential stuffing".

Using the site is simple: users enter their email address, and the service returns a list of breaches that included that address, along with what types of data were stolen (e.g., passwords, birthdates, or IP addresses). If a compromise is found, the immediate remediation step is to change the password for that account and any other account where that password was reused, and to enable Multi-Factor Authentication (MFA). Checking this site regularly is a standard "best practice" for maintaining high levels of information security hygiene in a landscape where data breaches occur with increasing frequency.