In malware terminology, what do we call a computer virus that deliberately targets and attempts to disable or evade anti-virus programs to prevent its own detection?

Introduction / Context:
Different malware categories are defined by behavior. Some spread autonomously, some disguise themselves, and others attempt to neutralize security tools. This question focuses on the class of malware that attacks anti-virus programs to avoid being found.

Given Data / Assumptions:

• Behavior in focus: actively countering or disabling anti-virus defenses.
• We must choose the term widely used in security literature for such behavior.

Concept / Approach:
A 'retrovirus' (in computer-security jargon) is designed to hinder, corrupt, or disable security software and its updates, thereby preventing detection or removal. This differs from propagation method (worm) or disguise method (trojan).

Step-by-Step Solution:

Verification / Alternative check:
Security glossaries and malware analyses frequently describe retroviruses as anti-AV attacking malware, sometimes also called anti-antivirus malware or AV-killer components within a larger malware family.

Why Other Options Are Wrong:

• Worm: Primarily defined by self-replication over networks; may not specifically target AV software.
• Trojan: Delivery via deception; not necessarily attacking security tools.
• Ghost virus: Not a standard category; an informal term at best.

Common Pitfalls:
Assuming any stealthy malware is a trojan; trojan describes disguise, not necessarily anti-AV aggression. The hallmark here is attacking detection mechanisms, hence 'retrovirus'.

Final Answer:
Retrovirus