In an IDS/IPS, which type of alarm occurs when legitimate traffic is improperly identified as malicious traffic?

A false-positive is an alert generated by a security system, such as an IDS/IPS, that incorrectly identifies benign or legitimate activity as malicious. The system "positively" identifies a threat, but this conclusion is "false." These events are common in security monitoring and require analysts to tune detection rules to improve accuracy and reduce the noise of unnecessary alerts, which could otherwise lead to alert fatigue and the masking of genuine threats.

B. True-negative: This occurs when the system correctly identifies legitimate traffic as non-malicious and allows it to pass without generating an alert.
C. False-negative: This is a critical security failure where the system fails to detect actual malicious traffic, incorrectly classifying it as benign.
D. True-positive: This is the desired outcome, where the system correctly identifies malicious traffic and generates an accurate alert.

1. Palo Alto Networks. (2020). Cybersecurity Survival Guide: A CISO's Companion. Chapter 4: Defending the Network

Section: "Intrusion Detection and Prevention Systems (IDS/IPS)". The guide defines a false positive as

"An alert that indicates malicious activity is occurring

but is triggered by legitimate

benign traffic."

2. Stallings

W.

& Brown

L. (2018). Computer Security: Principles and Practice (4th ed.). Pearson. Chapter 8: Intrusion Detection

Section 8.1: "Intruders

" subsection "Intrusion Detection." This foundational text

widely used in university curricula

defines a false positive as an event where "authorized users are identified as intruders."

3. Palo Alto Networks. (2023). PAN-OS® Administrator’s Guide 10.2. Section: "Monitor > Logs > Threat". The documentation explains that reviewing threat logs is necessary to "determine if the firewall is detecting threats correctly (true positives) or if it is incorrectly identifying traffic as a threat (false positives)." This confirms the operational definition within the Palo Alto Networks ecosystem.