Intrusion Detection System (IDS) Types: What You Should Know

By Tibor Moes / Updated: June 2023

Intrusion Detection System (IDS) Types: What You Should Know<br />

Intrusion Detection System (IDS) Types

Picture your home’s security system. It alarms if someone breaks in, right? Now, imagine that on a much larger, more complex scale. That’s what Intrusion Detection Systems (IDS) do for our networks. They’re our digital watchdogs, always on guard, ready to alert us to any cyber threats.


An Intrusion Detection System (IDS) is a network security tool that monitors and detects suspicious activity or violations in a system or network, serving as a digital watchdog for potential cyber threats.

Type 1 – Anomaly-Based IDS: These systems are like the Sherlock Holmes of cyber security. They establish a ‘normal’ network behavior, and when something deviates from this baseline, they’re on the case! They’re particularly good at detecting previously unknown threats, much like Sherlock uncovering clues no one else sees.

Type 2 – Signature-Based IDS: Think of these as the librarians of network security. They’ve got a vast library of known threats and attack patterns, and they’re always on the lookout to match current activity with their archives. They’re the best defense against recognized and often repeated cyber threats.

Type 3 – Hybrid IDS: This is like your ultimate, all-in-one security guard. It combines the best of both anomaly and signature-based systems. Not only can it match known threats, but it’s also capable of detecting new ones. This type of IDS brings together the strengths of both systems, providing comprehensive coverage against a wide range of cyber threats.

Don’t become a victim of cybercrime. Protect your devices with the best antivirus software and your privacy with the best VPN service.

Intrusion Detection System (IDS) Types In-depth

Anomaly-Based Intrusion Detection System (IDS)

Let’s dive into the fascinating world of Anomaly-Based IDS. Picture yourself walking into your favorite coffee shop. You’ve been there so often that you know its everyday rhythm like the back of your hand. The aroma of coffee, the barista’s friendly greeting, the soft background music – everything is as it should be. But one day, you step in and something’s off. The smell of burnt toast fills the air and there’s heavy metal music blaring from the speakers. Instantly, you know something’s not right.

That’s what an Anomaly-Based IDS does for your computer network. It spends a good deal of time learning the regular patterns, the daily routines, the ‘normal’ behavior of your network. It’s as if it’s getting to know every nook and cranny, every usual packet of data that travels across your network, becoming your network’s best friend.

So, when suddenly there’s a surge in data transfers at 3 AM, or an unexpected download from an unfamiliar website, it raises a red flag. Much like you did in the coffee shop, the Anomaly-Based IDS senses the deviation from the norm, and instantly sends out an alert.

This IDS type’s ‘Spidey senses’ make it exceptional at detecting unknown threats. It’s not just looking for the usual suspects, it’s also prepared for the unfamiliar ones. If a brand new threat slips past other defenses, the Anomaly-Based IDS will still catch it because it’s looking for odd behavior, not specific individuals.

But, like any superhero, Anomaly-Based IDS has its Achilles’ heel. While it’s fantastic at detecting new threats, it can sometimes mistake normal network behavior for an attack if it’s slightly out of the usual pattern. We call these “false positives.” However, with regular fine-tuning, these can be minimized to keep the network safe and the alerts meaningful.

In the realm of cybersecurity, Anomaly-Based IDS acts as our early warning system, our digital ‘sixth sense’ that keeps a keen eye on all network behavior. Its ability to spot unusual activity helps us stay a step ahead of the cybercriminals, securing our networks against the threats of the digital world.

Signature-Based Intrusion Detection System (IDS)

Imagine that you’re a detective with an extensive database of known criminals and their typical modes of operation. A crime occurs, and based on the evidence at hand – the method, the tools left behind – you flip through your mental Rolodex, identifying the criminal based on their signature style. That’s the essence of a Signature-Based IDS.

Just as every artist has their signature style, so do hackers when orchestrating cyber attacks. These distinctive patterns are like a digital ‘fingerprint’ that, when recognized, can immediately identify the source of a potential threat. And that’s where Signature-Based IDS comes in, acting as the tireless detective in our network security setup.

The Signature-Based IDS has a comprehensive library of known attack patterns, each representing a different type of cyber threat. It could be a specific sequence of data packets that indicates a DDoS attack, or a particular type of code injection that smells like an SQL injection. These patterns, also known as ‘signatures,’ are the IDS’s most valuable asset.

Much like our detective, the Signature-Based IDS is continuously on the case, comparing ongoing network activities with its vast archive of known threats. The moment it recognizes a match, it jumps into action, sending out an alert that an attempted intrusion is in progress.

Its strength lies in its ability to quickly recognize known threats, making it a formidable line of defense against the most common cyber attacks. However, it does have its limitations. Just as our detective might struggle with a completely new crime pattern, so too can a Signature-Based IDS struggle with unknown or zero-day threats. But when used in combination with other types of IDS, it forms a crucial part of any robust cyber defense strategy.

To sum it up, our Signature-Based IDS is the meticulous detective of our digital world. It leverages its extensive knowledge of known threats to keep our networks secure, always alert, always ready to spot the familiar signs of cyber foul play.

Hybrid Intrusion Detection System (IDS)

Let’s think of a Swiss Army knife for a moment. It’s not just a knife; it’s also a screwdriver, a bottle opener, a pair of scissors, and so much more. It combines the strengths of many tools, making it one of the most versatile things you can have in your pocket. That’s the spirit behind a Hybrid IDS. It’s the ‘Swiss Army knife’ of cybersecurity systems.

A Hybrid IDS takes the superpowers of both the Anomaly-Based and Signature-Based IDS and combines them into a single, comprehensive system. Like a vigilant night watchman with a high-tech security panel, it’s ready to spring into action, whether the threat is a known criminal or an unfamiliar face.

From the Anomaly-Based IDS, our Hybrid system inherits the ability to sense anything unusual in the network. It learns the standard behavior of the system, keeping an eagle eye out for any sudden changes, any deviations from the norm. This makes it well-equipped to catch zero-day attacks, those tricky new threats that other systems might miss.

On the other hand, it gets from the Signature-Based IDS an extensive library of known attack patterns. It uses this knowledge to swiftly identify common threats, reacting quickly when it sees a familiar ‘face’ in the crowd.

In other words, the Hybrid IDS offers the best of both worlds. It’s like having both a detective with an encyclopedic knowledge of criminals and a wise friend who can sense when something’s off. Together, these capabilities make the Hybrid IDS an effective and versatile guard against a wide variety of cyber threats.

That said, a Hybrid IDS does require careful management. Its dual nature means it needs regular updating and fine-tuning to stay sharp and avoid unnecessary alerts. But with the right maintenance, it can be a powerful tool in your cybersecurity toolbox.

In conclusion, the Hybrid IDS is the ‘Swiss Army knife’ of intrusion detection. With its ability to spot both familiar and novel threats, it stands as a comprehensive and effective solution, ensuring the highest level of security for our networks in the ever-evolving landscape of cybersecurity.


Navigating the digital landscape is much like exploring a bustling city. There are exciting opportunities and destinations, but we also need to be mindful of potential threats. Intrusion Detection Systems, whether they’re Anomaly-Based, Signature-Based, or Hybrid, are our trusted guides and guardians, each with its unique strengths. They enable us to explore this digital city safely, alerting us to possible dangers, from the familiar to the unknown. As we venture further into the world of cybersecurity, we can be confident that these systems will continue to evolve, providing us with the robust and comprehensive protection we need.

How to stay safe online:

  • Practice Strong Password Hygiene: Use a unique and complex password for each account. A password manager can help generate and store them. In addition, enable two-factor authentication (2FA) whenever available.
  • Invest in Your Safety: Buying the best antivirus for Windows 11 is key for your online security. A high-quality antivirus like Norton, McAfee, or Bitdefender will safeguard your PC from various online threats, including malware, ransomware, and spyware.
  • Be Wary of Phishing Attempts: Be cautious when receiving suspicious communications that ask for personal information. Legitimate businesses will never ask for sensitive details via email or text. Before clicking on any links, ensure the sender's authenticity.
  • Stay Informed. We cover a wide range of cybersecurity topics on our blog. And there are several credible sources offering threat reports and recommendations, such as NIST, CISA, FBI, ENISA, Symantec, Verizon, Cisco, Crowdstrike, and many more.

Happy surfing!

Frequently Asked Questions

Below are the most frequently asked questions.

What's the main difference between Anomaly-Based IDS and Signature-Based IDS?

Anomaly-Based IDS learns the ‘normal’ behavior of your network and raises an alert when it detects unusual activity, making it excellent for spotting new or unknown threats. On the other hand, Signature-Based IDS has a library of known threats and checks if current activity matches these known patterns, which makes it highly efficient at detecting recognized threats.

Can I use more than one type of IDS?

Absolutely! In fact, using a combination of IDS types can offer more comprehensive protection. The Hybrid IDS, for example, combines the strengths of both the Anomaly-Based and Signature-Based IDS, providing both the ability to detect known threats and the sensitivity to spot unusual behavior that might indicate a new kind of attack.


How can I minimize false positives in an Anomaly-Based IDS?

Minimizing false positives in an Anomaly-Based IDS involves regular fine-tuning of the system. This could mean adjusting the parameters of what’s considered ‘normal’ behavior, based on an understanding of the network’s patterns and routines. Regular updates and maintenance can also help keep the system informed and accurate, reducing the chances of false alarms.

Author: Tibor Moes

Author: Tibor Moes

Founder & Chief Editor at SoftwareLab

Tibor is a Dutch engineer and entrepreneur. He has tested security software since 2014.

Over the years, he has tested most of the best antivirus software for Windows, Mac, Android, and iOS, as well as many VPN providers.

He uses Norton to protect his devices, CyberGhost for his privacy, and Dashlane for his passwords.

This website is hosted on a Digital Ocean server via Cloudways and is built with DIVI on WordPress.

You can find him on LinkedIn or contact him here.

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