What type of insider attack involves an employee intentionally hiding company secrets using steganography?

The correct choice for the type of insider attack involving an employee intentionally hiding company secrets using steganography is a malicious insider. This term refers to individuals within an organization who exploit their privileged access for unethical or illegal gains, which includes actively hiding sensitive information.

Steganography is a technique used to conceal data within other non-suspicious files, like images or audio, making it a sophisticated way for an insider to exfiltrate information without raising alarms. A malicious insider typically has the intent to harm the organization, whether for personal gain or to damage the company.

Other options like a disgruntled employee, negligent insider, or professional insider may involve varying motivations or levels of intent that do not specifically include the deliberate concealment of data. A disgruntled employee may act out of anger or frustration, while a negligent insider might unintentionally expose data without malicious intent. A professional insider usually refers to someone whose expertise is leveraged for business purposes rather than illicit activities. Therefore, the most fitting description for this situation is a malicious insider, as it involves both intent and the specific act of hiding information through advanced methods like steganography.