What is a common issue with intrusion detection systems (IDS)?

A common issue with intrusion detection systems (IDS) is their tendency to generate false positives. This phenomenon occurs when the system mistakenly identifies legitimate activity as malicious or a security threat. Intrusion detection systems rely on predefined rules, patterns, or heuristic analysis to monitor network traffic and detect potential intrusions. However, because they evaluate a wide range of activities against these criteria, benign actions can sometimes trigger alerts, leading to notifications that may not correspond to actual security incidents.

This issue is significant because it can overwhelm security teams with alerts that require investigation, potentially leading to alert fatigue. Security professionals might waste valuable time and resources investigating false alarms instead of focusing on genuine security threats. Additionally, high false positive rates can result in damaged trust in the IDS system and the potential for real threats to be overlooked amidst the noise.

In contrast, the other options do not accurately capture the challenges associated with IDS. The technology is not always accurate in detecting threats—thus, claiming they are always accurate is misleading. While support for encrypted services can be a feature of some advanced systems, many IDS have limitations in analyzing encrypted traffic without proper decryption capabilities. Finally, while costs can vary based on the type of IDS and the scale of deployment, not all IDS are inexpensive; in