1. False positives: An IDS can generate false positives, which are alerts triggered by normal network traffic. For example, an IDS may detect a port scan when a legitimate user is simply checking email.
2. False negatives: An IDS may also fail to detect malicious activity. For example, an IDS may not detect a new type of malware or a zero-day attack.
3. High volume of alerts: IDSs generate a large number of alerts, which can be difficult to manage and investigate.
4. Resource utilization: IDSs require resources, such as processing power and storage space, to function properly.
5. Evasion techniques: Attackers can use evasion techniques to bypass IDSs. For example, an attacker may split a malicious payload into multiple packets to avoid detection.
6. Complexity: Many IDSs are complex and require extensive training to configure and manage.