This document discusses responding to a data breach, including identifying if a breach has occurred, investigating the breach, containing the breach, fixing vulnerabilities, assembling a breach response team, and determining notification obligations. It provides an overview of steps to take in the first 24 hours of discovering a breach, such as securing premises, stopping additional data loss, and assessing risks. It also outlines some state-specific notification requirements, such as notifying various government agencies in Massachusetts and the Superintendent of Financial Services in New York within 72 hours of certain cybersecurity events.