What is the Difference Between Network-Based Intrusion Detection Systems and Host-Based Intrusion Detection Systems?

In the field of cyber security, you’ll commonly see the terms ‘network-based intrusion detection system’ (NIDS) and ‘host-based intrusion detection system’ (HIDS) being used.

Considering that the global Intrusion Detection Systems (IDS) market was valued at USD 5063.21 Million in 2022 and is estimated to reach USD 7008.32 Million by 2028, the terms NIDS and HIDS frequently echo in the realm of cyber security.

But what exactly do these terms mean? And more importantly, what is the difference between them?

We explore these two types of intrusion detection systems, shedding light on their unique characteristics, advantages, and disadvantages.

Defining intrusion detection systems

Before we dive into the differences between network-based intrusion detection systems and host-based intrusion detection systems, it is crucial to understand what an intrusion detection system (IDS) is.

An IDS is a device or software application that monitors a network or systems for malicious activity or policy violations. It is a critical component of modern cyber security strategies.

IDS can be classified into two types: network-based and host-based.

Both types of IDS serve the same purpose, which is to detect suspicious activity that could potentially harm the system or network.

However, the way they achieve this goal differs significantly, as we will explore in the following sections.

Network-based intrusion detection system (NIDS)

A network-based intrusion detection system, or NIDS, is a system used to monitor and analyse network traffic to protect a system from network-based threats.

It is typically installed at a strategic point within the network to monitor inbound and outbound traffic to all devices on the network.

A network-based intrusion detection system examines the traffic that passes through the entire subnet, inspecting each packet and comparing it against a database of known attacks.

If a match is found, the network-based intrusion detection system will then alert the system or network administrator.

This makes NIDS particularly effective at identifying and thwarting large-scale, network-wide attacks.

Advantages of NIDS

One of the main advantages of NIDS is its ability to monitor a large network. This makes it an excellent choice for organisations with large networks, where installing an IDS on every device would be impractical.

Another advantage of network-based intrusion detection systems is that they provide a holistic view of the network traffic, making it easier to detect patterns that may indicate a coordinated attack.

Furthermore, since NIDS is not installed on a specific host, it is less likely to be affected by a successful attack on a host.

Disadvantages of NIDS

While a network-based intrusion detection system has many advantages, it also has some disadvantages.

One of the main disadvantages is that it can generate a high number of false positives, as it may misinterpret normal network traffic as malicious.

This can lead to unnecessary alerts and potentially disrupt normal operations.

Another disadvantage of NIDS is that it can be blind to encrypted traffic, as it cannot inspect the contents of encrypted packets.

This means that if an attacker uses encryption, the NIDS may not be able to detect the attack.

Host-based intrusion detection system (HIDS)

A host-based intrusion detection system, or HIDS, is an intrusion detection system that is installed on a specific host or device within the network.

Unlike NIDS, which monitors network traffic, HIDS monitors the inbound and outbound packets from the device only and will alert the user or administrator if suspicious activity is detected.

HIDS operates by analysing the system’s internals, such as system calls, application logs, and file-system modifications.

If it detects any activity that deviates from the norm, it will trigger an alert.

Advantages of HIDS

One of the main advantages of HIDS is its ability to monitor the internal workings of a host. This makes it an excellent choice for detecting attacks that are targeted at specific hosts, such as rootkits and other types of malware.

Another advantage of HIDS is that it can monitor encrypted traffic.

Since it is installed on the host itself, it can inspect the contents of encrypted packets, making it more effective at detecting attacks that use encryption.

Disadvantages of HIDS

While HIDS has many advantages, it also has some disadvantages. One of the main disadvantages is that it can be resource-intensive, as it needs to monitor the system’s internals.

This can lead to performance issues, especially on older or less powerful devices.

Another disadvantage of HIDS is that it can only monitor a single host.

This means that if an organisation has a large network, it would need to install a HIDS on every device, which can be impractical and costly.

Conclusion

Choosing between a network-based intrusion detection system and a host-based intrusion detection system depends on the specific needs and resources of an organisation.

Larger organisations with extensive networks may benefit more from NIDS, while smaller organisations or those with specific security concerns may find HIDS more suitable.

In many cases, a combination of both NIDS and HIDS may provide the most comprehensive protection.

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