Data exfiltration is the unauthorized transfer of sensitive information from a computer or network to an external destination, often by cybercriminals. This process typically involves stealing confidential data such as personal records, financial details, or intellectual property, and sending it outside the organization without permission. Data exfiltration can occur through various methods, including malware, phishing attacks, or exploiting security vulnerabilities. The goal is usually to use, sell, or ransom the stolen data, making it a serious threat to individuals and organizations alike.