What triggers a log event during access to cardholder data?

The correct choice identifies that all invalid user logins trigger a log event during access to cardholder data. This is crucial for maintaining security and integrity in systems handling sensitive data, like cardholder information. Recording all invalid login attempts is essential for multiple reasons:

1. Security Monitoring: Tracking invalid logins helps security teams identify potential unauthorized access attempts or brute-force attacks, where an attacker tries multiple passwords to gain access. This kind of monitoring is vital for safeguarding cardholder data.

2. Incident Response: The logs created from these events can serve as an important forensic tool. In the event of a security breach, historical logs of invalid login attempts can help assess how the breach occurred and allow for a more effective response and mitigation strategy.

3. Compliance: For businesses that must comply with security standards and regulations, logging all access attempts—whether successful or unsuccessful—may be a requirement. This ensures that security controls are in place and functioning as intended.

By logging events triggered by all invalid user logins, organizations can better manage their risk associated with accessing cardholder data and maintain a comprehensive view of their security posture.