Which type of intrusion detection system (IDS) can only be passive?

Which type of intrusion detection system (IDS) can only be passive?

• A. Network-based intrusion detection system (NIDS).
• B. Application-based intrusion detection system.
• C. Host-based intrusion detection system (HIDS).
• D. Open system interface (OSI) layer 4 IDS.

Answer: (A)

The correct response highlights that the Network-based Intrusion Detection System (NIDS) is inherently a passive system. This type of IDS is designed to monitor the entire network for suspicious traffic patterns and behaviors. It analyzes data packets traveling through the network in real-time, but it does not have the capability to actively disrupt or block potentially malicious activity. Instead, a NIDS provides alerts to network administrators when it detects suspicious behavior, allowing them to respond appropriately without interfering with network operations. In contrast, other types of intrusion detection systems may incorporate active measures that enable them to react to threats immediately. For example, a Host-based Intrusion Detection System (HIDS) may engage in active monitoring of files and system calls to detect integrity issues or unauthorized access, potentially reacting by quarantining files or logging off users. An application-based IDS focuses on the application layer and can also implement protective measures, depending on its design, often not strictly limited to passive functions. The option referring to OSI layer 4 potentially indicates a focus on transport-level traffic monitoring, which may imply an active component in how data is managed. Understanding the passive nature of NIDS emphasizes its role in surveillance and alerting rather than intervention, reinforcing its position as a key tool for network security

The correct response highlights that the Network-based Intrusion Detection System (NIDS) is inherently a passive system. This type of IDS is designed to monitor the entire network for suspicious traffic patterns and behaviors. It analyzes data packets traveling through the network in real-time, but it does not have the capability to actively disrupt or block potentially malicious activity. Instead, a NIDS provides alerts to network administrators when it detects suspicious behavior, allowing them to respond appropriately without interfering with network operations.

In contrast, other types of intrusion detection systems may incorporate active measures that enable them to react to threats immediately. For example, a Host-based Intrusion Detection System (HIDS) may engage in active monitoring of files and system calls to detect integrity issues or unauthorized access, potentially reacting by quarantining files or logging off users. An application-based IDS focuses on the application layer and can also implement protective measures, depending on its design, often not strictly limited to passive functions. The option referring to OSI layer 4 potentially indicates a focus on transport-level traffic monitoring, which may imply an active component in how data is managed.

Understanding the passive nature of NIDS emphasizes its role in surveillance and alerting rather than intervention, reinforcing its position as a key tool for network security