What are the Two Main Types of Intrusion Detection Systems?

For absolute beginners in the world of intrusion detection systems (IDS), it is important to know the difference between the various types of intrusion detection systems in cyber security. This blog details the difference between the two main types of IDS and their different detection methods and then discusses the challenges of IDS tools and the types of intrusions commonly seen in cyber security.

What are the two main types of intrusion detection systems?

There are two main types of Intrusion Detection Systems in cyber security based on their deployment and data source:

1. Network Intrusion Detection System (NIDS): NIDS act as network monitoring devices deployed at strategic points within a computer network. Their primary function is to continuously capture and analyze network traffic data traversing a specific network segment. NIDS can be implemented in two primary ways:

• Dedicated hardware appliances: These are specialized devices solely designed to perform NIDS functions.
• Software applications on network servers: Existing network servers can be leveraged to host NIDS software, enabling them to perform network traffic analysis alongside other server functionalities.

NIDS typically utilizes network adapter promiscuous mode. This mode allows the NIDS to capture all network traffic on the attached network segment, regardless of its intended recipient. NIDS employs two main techniques for analyzing captured network traffic data: signature-based detection and anomaly-based detection.

2. Host-Based Intrusion Detection System (HIDS): In contrast to NIDS which focuses on network traffic analysis, HIDS provides security for individual devices (hosts) within the network. HIDS function as software agents deployed directly on the operating system of the host device itself. Their primary function is to monitor and analyze activity occurring on the host device. HIDS are deployed as software agents on individual servers, desktops, or laptops within the network. A single HIDS agent is typically installed on each host device for dedicated monitoring.

HIDS collects data from various sources on the host device, including:

• System logs: These logs record events and activities within the operating system of the host device.
• File access attempts: HIDS monitors attempts to access files on the host device, including successful and failed attempts.
• Running processes: HIDS maintains a record of processes currently running on the host device.

HIDS primarily utilizes anomaly-based detection techniques. By analyzing the collected data, HIDS establishes baselines for typical host activity. Significant deviations from these baselines, such as unusual file access attempts or unexpected processes running, can indicate potential intrusions or suspicious behavior.

What are the two primary categories of detection?

There are two primary methods of IDS/IPS detection, anomaly-based and signature-based, but it is also important to mention the third method, hybrid. These methods define how the IDS analyzes data to identify potential intrusions.

• Anomaly-Based IDS: Anomaly-based IDS focuses on identifying deviations from normal behavior within a network or system. It works by establishing a baseline for normal activity by statistically analyzing network traffic or system activity over time. This baseline becomes a reference for identifying anomalies. The IDS then continuously monitors network traffic or system activity and compares the real-time data to the established baselines. Significant deviations from these baselines are flagged as potential intrusions.
• Signature-Based IDS: A signature-based intrusion detection system relies on a predefined database of attack signatures to identify malicious activity. These signatures represent known patterns or fingerprints of network attacks or suspicious system behavior. The IDS continuously monitors network traffic or system activity and compares this data against the database of attack signatures. Any matches trigger an alert, indicating a potential intrusion attempt.
• Hybrid IDS: A hybrid intrusion detection system combines both anomaly-based and signature-based detection methods to address the limitations of each approach. A hybrid system leverages signature-based detection for known threats and anomaly-based detection for novel attacks. This enhances the overall effectiveness of intrusion detection.

Each of these three detection methods (Anomaly-based, Signature-based, Hybrid) offers different strengths and weaknesses. Choosing the most suitable approach depends on factors like the specific security requirements of the network, the resource availability for managing the IDS, and the acceptable level of false positives.

What are the limitations and challenges of intrusion detection systems?

Intrusion detection systems (IDS) are a valuable tool for cybersecurity, but they do have limitations and challenges that users should be aware of. Here are some key points to consider:

• False Positives and False Negatives: A major challenge with IDS is the potential for generating both false positives and false negatives. A false positive occurs when the IDS mistakenly flags normal activity as suspicious, wasting time and resources for security personnel investigating these non-threats. False negatives happen when the IDS fails to detect actual malicious activity, potentially leaving your system vulnerable. Factors like outdated signatures, misconfigured rules, or novel attack techniques can contribute to both issues.
• Limited Visibility: Network-based IDS (NIDS) primarily focus on network traffic analysis and might miss threats that don't involve network activity. Additionally, encrypted traffic can be difficult for NIDS to analyze, potentially allowing malicious activity to slip through undetected. Host-based IDS (HIDS) can provide better visibility into individual devices, but they can't offer a holistic view of the entire network.
• Resource Consumption: Running IDS can consume significant computing resources, depending on the type of IDS and the volume of network traffic or system activity it needs to analyze. This can be a concern for organizations with limited resources.
• Evolving Threats: Cybersecurity threats are constantly evolving, and attackers are always developing new techniques to bypass detection methods. IDS rely on signatures or baselines to identify threats, and they may struggle to detect novel attacks that haven't been defined yet. Keeping IDS signatures and configurations up-to-date is critical to maintaining effectiveness.
• Alert Fatigue: A constant stream of IDS alerts, even if some are false positives, can overwhelm security personnel. This can lead to alert fatigue, where they become desensitized to alerts and miss important ones.
• Insider Threats: IDS are primarily focused on detecting external threats and may not be effective in identifying malicious activity by authorized users within the network (insider threats). These threats require additional security measures like user activity monitoring and access controls.

It is important to note that all of these challenges can be solved by using a more advanced modern alternative such as network detection and response (NDR). The Stamus Security Platform (SSP) is a modern NDR solution that leverages the best from IDS technology without the same challenges faced by IDS users. Learn more at https://www.stamus-networks.com/stamus-security-platform.

What are the three types of intrusion?

The term "intrusion" in the context of cybersecurity can have a broad meaning, but it often refers to unauthorized access attempts or efforts to compromise the confidentiality, integrity, or availability of a computer system or network. Here are three common types of intrusions in cyber security to be aware of:

1. Network Intrusions: These involve unauthorized access attempts to a computer network. Attackers might try to gain access to sensitive data, disrupt network operations, or install malware on connected devices. Examples include:
2.  
   • Port scanning: Attackers probe a network to identify open ports and vulnerabilities on connected devices.
   • Denial-of-service (DoS) attacks: Attackers overwhelm a system with traffic, making it unavailable to legitimate users.
   • Man-in-the-middle (MitM) attacks: Attackers intercept communication between two parties and eavesdrop on or alter the data exchange.
3. System Intrusions: These involve unauthorized access attempts to a specific computer system. Once attackers gain access, they might steal data, install malware, or disrupt system operations. Examples include:
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   • Password cracking: Attackers use various techniques to guess or brute-force a user's password.
   • Exploiting software vulnerabilities: Attackers leverage known weaknesses in software to gain unauthorized access to a system.
   • Privilege escalation: Attackers exploit vulnerabilities to gain higher privileges within a system, allowing them to access unauthorized resources or perform unauthorized actions.
5. Social Engineering Attacks: These attacks rely on human manipulation rather than exploiting technical vulnerabilities. Attackers trick or deceive users into giving away sensitive information, clicking malicious links, or installing malware. Examples include:
6.  
   • Phishing attacks: Attackers send emails or messages impersonating a legitimate entity to trick users into revealing sensitive information.
   • Pretexting: Attackers create a false scenario to gain a user's trust and obtain confidential information.
   • Baiting: Attackers lure users into clicking on malicious links or downloading malware by offering something attractive or exploiting fear.

It's important to note that these categories can sometimes overlap. For instance, a social engineering attack might be used to gain access to a network (network intrusion) or a system (system intrusion). By understanding these different types of intrusions, organizations can implement appropriate security measures to mitigate risks.

Explore a modern alternative

IDS is undoubtedly a powerful and effective means to detect known threats on your organization’s network. Unfortunately, most IDS deployments are riddled with false positives, provide limited threat detection, and lack sufficient visibility into anomalous activity and subtle attack signals. Traditional IDS vendors have failed to innovate in ways that solve these challenges, leading to inefficient or downright ineffective threat detection.

You need a network security platform that doesn’t generate an endless stream of useless alerts across part of your network, and instead automatically identifies alerts of interest and notifies you of only serious and imminent threats. Your organization deserves response-ready detection with visibility into your entire network regardless of the environment with easy access to all the contextual evidence you need to stop an attack before it can cause damage. Replace your legacy IDS with a modern network detection and response platform that gives you these features and more.

The Stamus Security Platform™ is a network-based threat detection and response solution that eliminates the challenges of legacy IDS while lowering your response time. Stamus Security Platform harnesses the full potential of your network, bringing state-of-the-art threat detection, automated event triage, and unparalleled visibility to the security team.

Book a demo to see if the Stamus Security Platform is right for your organization.