The Cybersecurity Information Sharing Act of 2015 is a U.S. law associated with voluntary exchange of cyber threat information between private organizations and government entities. It established a framework intended to make sharing easier, including certain legal protections for qualifying disclosures and privacy-related requirements for handling information.
In practice, organizations may share indicators such as malicious IP addresses, domains, or file hashes, along with relevant context about threats. This information can help defenders update detections, investigate activity, or strengthen defenses. The law does not make shared data automatically accurate or useful: recipients still need to assess its quality, context, and handling requirements. Technical programs such as CISA’s Automated Indicator Sharing support machine-readable exchanges, but effective defense depends on timely, actionable information and sound operational processes.