Cybercriminals and cybersecurity experts have been playing cat and mouse for decades. Every advance in cyber-defense technology is the result of commensurate advancements in hacking and other cybercrime methodology. This results in a seemingly endless variety of attack vectors to navigate.
There are also many types of intrusion detection systems to match the array of threats facing businesses.
What are the Types of Intrusion Detection Systems?
With all the different IDS options available, it can be hard to keep track of what’s best for your company. This guide breaks down everything you need to know about the types of intrusion detection and prevention systems across three sections devoted to primary categories:
- Intrusion detection systems based on the location of detection (host or network-based)
- Intrusion detection systems based on the method of detection (anomalies or signatures)
- Intrusion prevention systems and how to integrate them into holistic managed IT security
By the end of this article, you’ll be well prepared to install one or more detection or prevention systems in your cybersecurity infrastructure. But first, let’s define some basic terminology.
What Are Intrusion Detection and Prevention Systems?
An intrusion detection system (IDS) is any capacity within a security framework that scans for attacks, breaches, and other cybersecurity incidents. In some cases, an IDS functions independently from other security controls designed to mitigate these events. In other instances, IDS is integrated into a broader security information event management system (SIEM). Examples include comprehensive intrusion detection and prevention systems.
An IDS proper is concerned primarily with detecting attacks, while an intrusion prevention system is dedicated to preventing them. This means scanning for intrusions and risks that may lead to attacks. One example is a robust managed detection and response program.
Intrusion Detection Based on Point of Detection
The first primary type or category of IDS is characterized by where the IDS is set up within the cybersecurity architecture and where it detects the intrusions. Within the category of IDS based on the location of detection, there are two subcategories or subtypes:
- Host-based intrusion detection systems (HIDS)
- Network-based intrusion detection systems (NIDS)
In some cases, companies may use both subcategories or a hybrid that takes on the qualities of each. Let’s take a closer look at both of them, how they work, and their respective pros and cons.
Host-Based Intrusion Detection Systems
The first subtype of IDS, a host-based intrusion detection system (HIDS), exists on one host or individual endpoint within the broader network. It was the original form of IDS and functions straightforwardly, acting as a device-specific filter for all incoming and outgoing traffic.
Typically, a HIDS functions by comparing the given host’s current state at regular intervals to a past baseline of that host at optimal security or integrity. Any irregularities or ways in which the current state differs from the norm are flagged and analyzed against threat intelligence.
The simplicity of a HIDS may be a benefit or a challenge depending on the number, complexity, and interconnectedness of individual hosts within your company’s broader information networks.
Network-Based Intrusion Detection Systems
The second subtype of IDS, a network-based intrusion detection system (NIDS), exists in one or more strategic locations within your company’s networks. Similar to firewalls, they can operate as boundaries between sensitive points within the network. They often work alongside firewalls, screening packets, and other content before and after it passes through the wall or filter.
When working correctly, a NIDS optimizes systems around it by lessening the burden on firewalls and other controls. However, it suffers from the same limitations as any other web filtering mechanism: the most advanced and well-disguised attacks may elude its detection.
Intrusion Detection Based on Method of Detection
The second primary category or type of IDS is characterized by detecting intrusions, and the exact type of monitoring and analytical methodology it leverages. Within the category of IDS based on the method of detection, there are two subcategories or subtypes:
- Anomaly-based intrusion detection systems focused on unusual activities
- Signature-based intrusion detection systems focused on pattern recognition
As with location-based IDS, companies may use both of these subcategories or a hybrid. Again, let’s take a closer look at both of them, how they work, and their respective pros and cons.
Anomaly-Based Intrusion Detection Systems
The third subtype of IDS is a system that scans primarily for anomalies within the network or host. The IDS is programmed to operate on a dynamic set of rules that constitute a security baseline. In this way, it functions similarly to a HIDS but with flexibility for multiple hosts or entire networks.
The most enormous benefits of anomaly-based IDS programs involve attacks that are unknown or hard to trace — namely, some of the most sophisticated and multifaceted attacks. However, a major drawback of this approach is its potential to overestimate the threat of a given irregularity and incorrectly designate an activity as an intrusion, leading to costly misuse of mitigation resources.
Signature-Based Intrusion Detection Systems
The fourth and final subtype of IDS is a system that works by scanning for unique “signatures” that are indicative of an attack, attempted attack, or other dangerous forms of intrusion. This IDS also identifies irregularities by scanning for specific kinds of traffic and event traces.
A signature-based IDS system is especially effective at swiftly identifying and flagging known attacks. Where it struggles to provide much value is where anomaly-based IDS systems shine: attacks that are unknown or difficult to characterize. A hybrid IDS with elements of both is ideal.
Intrusion Prevention Systems and Best Practices
Detection of incidents is a critical step toward minimizing the harm of cybercrime. As a whole, IDS is most useful as a means toward incident prevention. Like IDS, prevention falls into four primary types:
- Host-based intrusion prevention systems focus on individual endpoints (like HIDS).
- Network-based intrusion prevention systems focus on whole networks (like NIDS).
- Wireless-based intrusion prevention systems focus on WiFi and clouds specifically.
- Network behavior analysis focuses on leveraging threat analysis to prevent intrusion.
Each of these approaches has its strengths and weaknesses, and many organizations find that a hybrid approach mixing elements of all four is best for their risk environment.
Benefits of Professional Incident Management Services
For many companies, the best approach to a cybersecurity concern is the one that’s simplest to implement. To that effect, RSI Security’s incident management includes six cyclical steps:
- Identification of incidents as soon as they occur on hosts or in the network
- Logging of incidents and immediate indexing against threat intelligence
- Diagnosis of incidents following a lengthy, complex analytical process
- Assignment of appropriate controls, responsibilities, and resources
- Resolution of the incident, including seizure and recovery of assets
- Continuity of business and customer satisfaction measures
Our team of experts can leverage any combination of the types detailed above, tailoring a plan for detection and response to your company’s specific needs and means. This includes compliance requirements and any other peculiarities of your cybersecurity architecture.
Professional Intrusion Detection and Prevention
This blog has covered a variety of intrusion detection and prevention system types. There are two primary approaches to intrusion detection. These break up into four primary types of intrusion detection systems. Concerning prevention, there are also four types to consider.
However, many companies can benefit from a simplified, comprehensive approach to intrusion detection and prevention. To find out just how powerful your intrusion prevention and overall security can be, contact RSI Security today!
Download Our Breach Response Checklist
Whether you’re in the midst of a breach or preparing a plan for the future – this checklist will give a good starting point for responding to a breach. Upon filling out this brief form you will receive the checklist via email.