Abstract: A cybersecurity system protects personally identifiable information (PII) of users on a computer network. A webpage received in an endpoint computer of the cybersecurity system is parsed to detect one or more input fields that ask a user of the endpoint computer for a PII. Instead of entering the PII of the user into an input field, a substitute value for the PII of the user is entered into the input field based at least on a website that served the webpage to the endpoint computer.