While all actions may eventually be justified, reviewing associated log files for suspicious activity should be the first immediate action. Patterns in security incidents, such as regular login failures, can be indicative of automated attacks, such as a brute force attempt, especially when occurring at odd hours. By reviewing log files, the analyst can identify the source, methods, and potentially compromised accounts. This directs further measures and a targeted investigation. Updating the IDS/IPS or informing legal only comes after confirming an incident, and implementing CAPTCHA is a preventive measure but doesn't address the immediate need to investigate the existing alerts.