Which of the following is the case when an IDS does not identify an actual attack?

A false negative occurs when an Intrusion Detection System (IDS) fails to detect an actual attack that is happening. In this scenario, the attack is real, but the IDS is unable to identify it, leading to a missed detection. This can be critical for cybersecurity, as it means that malicious activity may go unaddressed, allowing attackers to carry out their actions without any alerts or defenses being triggered.

When considering the term "false negative," it is important to understand that it directly impacts the effectiveness of the IDS. Ideally, the system should accurately identify and flag real threats; however, false negatives can lead to severe security gaps within an organization. This is in contrast to true positives, where an attack is correctly identified; true negatives, where normal, harmless activity is correctly identified as such; and false positives, where the IDS incorrectly flags benign activity as an attack. Understanding these concepts is vital for effectively assessing an IDS's performance and improving overall security measures.