Final answer:
To remediate the vulnerabilities after a data breach in which customer PII was compromised, a lead security analyst should use Root Cause Analysis.
Step-by-step explanation:
When addressing the problem of a data breach caused by an insider threat in which customer Personally Identifiable Information (PII) was compromised, the lead security analyst should consider using Root Cause Analysis (RCA) to remediate the vulnerabilities.
RCA is a methodology focused on identifying the fundamental causes of issues. In contrast to merely dealing with symptoms, RCA provides a deeper investigation into the series of events or conditions that led to the undesirable outcome, enabling more efficient and targeted remediation strategies.
Behavioral analytics could help in identifying unusual activities that indicate a potential threat, and Data Leak Prevention (DLP) mechanisms are more preventative, designed to protect data from exfiltration rather than investigate an existing breach.