What is a false positive in the context of an IDS?

In the context of an Intrusion Detection System (IDS), a false positive occurs when the system incorrectly identifies benign or legitimate traffic as malicious or a threat, leading to an alert that is not warranted. This is problematic because it can cause unnecessary alarm and potentially distraction from real threats, resulting in wasted resources as teams investigate and respond to these non-threats.

For instance, if a company’s IDS sends an alert indicating that normal employee activity is suspicious, this results in a false positive. Instead of a genuine attack being identified, the system fails to differentiate between innocent actions and actual malicious behavior. This misclassification can lead to security personnel being deployed to address an imaginary threat, diverting attention from more pressing security concerns.

The nature of a false positive highlights the challenges of effectively tuning and configuring IDS, as the goal is to minimize such occurrences while ensuring that actual threats are detected promptly.