Palo Alto Networks Certified Network Security Administrator (PCNSA)Cybersecurity FundamentalsMedium

A cybersecurity incident response team is analyzing a recent breach where an attacker gained initial access by exploiting a vulnerability in a web application. The vulnerability was previously unknown to the software vendor and had no available patch at the time of the attack. What term best describes this type of vulnerability?

  1. AMisconfiguration
  2. BZero-day vulnerability
  3. CLogic flaw
  4. DKnown vulnerability
Show answer & explanation

Correct answer: B. Zero-day vulnerability

A zero-day vulnerability is a software flaw that is unknown to the vendor and for which no patch exists, making it a highly dangerous attack vector, precisely matching the scenario described.

Why the other options are wrong

  • A. Misconfiguration refers to incorrect settings, not an inherent software flaw.
  • C. A logic flaw is an error in the design of the application's functionality, but the key aspect here is the 'unknown to vendor, no patch' element.
  • D. A known vulnerability would have been publicly disclosed and likely have a patch available.

Zero-day vulnerability

A software or hardware flaw that is unknown to the vendor and for which no official patch or fix has been released, making it a lucrative target for attackers.

  • Exploited before the vendor is aware or has a patch.
  • Highly dangerous due to lack of immediate defense.
  • Often used in targeted attacks by sophisticated adversaries.
  • Requires advanced detection methods like behavioral analysis.

Memory trick: Zero knowledge, zero days to patch.

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