What term describes a disgruntled employee who may pose a security threat?

The term that describes a disgruntled employee who may pose a security threat is "Malicious Insider." This term specifically refers to individuals within an organization who, due to personal grievances, dissatisfaction, or other motives, may exploit their access to sensitive information or systems to harm the organization. These insiders can intentionally leak information, sabotage operations, or engage in other malicious activities that pose risks to security.

Understanding this term is crucial in counterintelligence practices, as identifying and mitigating threats from within is just as important as protecting against external threats. Organizations need to be vigilant about the potential for current employees to misuse their access, particularly if they feel undervalued or wronged.

The other options do not align with the concept of an insider threat. For instance, a Subject Matter Expert refers to someone with deep knowledge in a specific area, which doesn't inherently relate to malicious intent. An Overqualified Candidate implies a person who may have more qualifications than needed for a position but does not indicate any predisposition towards harmful behavior. Cleared Laboratory refers to a secure facility where work is conducted that requires a security clearance, which again does not directly relate to disgruntled employees or insider threats.