A security engineer discovers that a spreadsheet containing confidential information for nine of their employees was fraudulently posted on a competitor's website. The spreadsheet contains names…

Checking for internal knowledge is a useful investigation step but does not address the immediate harm of publicly exposed employee PII that requires urgent remediation.

Reviewing communications for spoofed emails investigates a phishing vector unrelated to the incident, which involves data already posted on an external website.

Disconnecting from the internet would not remove data already hosted on the competitor's site and would cause unnecessary business disruption without addressing the root harm.

Because the data - including SSNs, salaries, and names - is already publicly posted, containment at the network level is no longer possible, and legal intervention is required to compel the competitor to remove it and to explore civil or criminal liability. Involving legal counsel also preserves the chain of custody for any evidence needed in litigation and ensures the organization meets breach notification obligations tied to exposed PII.