What limitations do intrusion detection and prevention systems have?

2 Evasion techniques

Another limitation of IDPS is that they can be evaded by attackers who use various techniques to bypass or deceive them. Some of the common evasion techniques are encryption, fragmentation, obfuscation, spoofing, and polymorphism. Encryption can hide the content of the network traffic from the IDPS, making it harder to detect malicious patterns. Fragmentation can split the network packets into smaller pieces that can avoid the IDPS filters or reassemble in a different order. Obfuscation can alter the appearance of the network traffic or the malware code to avoid matching the IDPS signatures or rules. Spoofing can fake the source or destination of the network traffic to mislead the IDPS or hide the attacker's identity. Polymorphism can change the malware code dynamically to avoid detection by the IDPS. To counter evasion techniques, you need to use IDPS that can decrypt, reassemble, normalize, and analyze the network traffic at different layers and use heuristic or behavioral methods.

3 Resource consumption

A third limitation of IDPS is that they can consume a lot of resources, such as bandwidth, memory, CPU, and disk space. This can affect the performance and availability of your network and your devices. Depending on the type, mode, and location of your IDPS, you may experience delays, bottlenecks, or failures in your network traffic or your applications. For example, if you use an inline IDPS that blocks or modifies the network traffic, you may introduce latency or errors in your communication. If you use a host-based IDPS that monitors the activity of your devices, you may consume the resources of your operating system or your applications. To optimize resource consumption, you need to balance your IDPS configuration, placement, and scalability with your network requirements and capabilities.

5 Human factors

A fifth limitation of IDPS is that they depend on human factors, such as skills, knowledge, and awareness. IDPS are not fully automated or intelligent systems that can operate without human intervention or supervision. They require human input, output, and feedback to function effectively and efficiently. You need to have the skills and knowledge to install, configure, maintain, and update your IDPS, as well as to analyze, interpret, and act on the alerts and reports that they generate. You also need to have the awareness and vigilance to monitor your network activity and your IDPS performance, and to respond to incidents and emergencies. To improve human factors, you need to invest in training, education, and awareness programs for yourself and your staff, and to use IDPS that have user-friendly and intuitive interfaces and features.