Correct Answer:
B. A security flaw unknown to the vendor.
Explanation:
The correct answer is A security flaw unknown to the vendor. because the term signifies that the developer or vendor has had zero days to create a security patch for the issue.
- Step 1 (Definition): A zero-day vulnerability is an unpatched software flaw that is completely unknown to the party responsible for fixing it, often discovered by attackers first.
- Step 2 (Exploitation): Because the vendor is unaware of the defect, no official defense or patch exists, making systems highly susceptible to targeted zero-day exploits.
- Incorrect Options:
- A bug fixed on the day of software release is incorrect because bugs patched at launch are known and resolved, not exposed security flaws.
- A virus that expires within 24 hours is incorrect because malware lifetime is not restricted by a mandatory 24-hour self-destruction timer.
- A hardware defect is incorrect because zero-day vulnerabilities primarily refer to flaws discovered within software code and system logic.