Highlights:
- Anomaly-based IDS was developed to detect unknown malware. It uses machine learning to create a model of normal activity. Any deviation from this model is flagged as suspicious.
- Some organizations deploy IDS and IPS as separate solutions, but it’s more common to integrate them into a single Intrusion Detection and Prevention System (IDPS).
The term “intrusion” usually refers to attackers gaining unauthorized access to a network, device, or system. Cybercriminals employ increasingly advanced methods to infiltrate organizations undetected. These methods include common tactics such as fragmentation, address spoofing, coordinated attacks, and pattern evasion.
An Intrusion Detection System (IDS) is a tool that monitors network traffic for known threats and suspicious activities. When it identifies potential security risks, it alerts IT and security teams. While most IDS solutions focus on detecting and reporting anomalies, some can also take proactive measures, such as blocking malicious traffic.
IDS tools are generally software-based that can run on the hardware or simply work as a network security solution. Besides, cloud-based IDS options protect resources, data, and systems within cloud environments.
Detection Methods of IDS
Exploring the diverse detection methodologies employed by IDS is crucial for optimizing threat identification and enhancing network security posture.
- Signature-based method
Signature-based IDS detects attacks by identifying specific patterns in network traffic, such as the number of bytes or sequences of 1s and 0s. It also recognizes known malicious instruction sequences used by malware. These patterns are called signatures. Despite effectively detecting attacks with existing signatures, it struggles to identify new malware with unknown patterns.
- Anomaly-based method
Anomaly-based IDS was developed to detect unknown malware. It uses machine learning to develop normal activity models. Any deviation from this model is flagged as suspicious. Unlike signature-based IDS, anomaly-based systems are more adaptable, as they can be trained to suit specific applications and network configurations.
While detection methods provide the foundation for how IDS identifies threats, understanding the various IDS types helps apply these methods to specific network security requirements.
Types of Intrusion Detection System
A comprehensive understanding of the different patterns of IDS is fundamental to selecting the right security approach for safeguarding network environments.
- Network intrusion detection system
It tracks traffic over the entire subnet, comparing it to a database of common attacks. If an attack is detected or unusual behavior is observed, it sends an alert to the administrator. For example, a Network-based IDS (NIDS) can be installed on the subnet with firewalls to detect attempts to breach the firewall.
- Host intrusion detection system (HIDS)
HIDS monitors incoming and outgoing packets on a device and alerts the administrator if it detects suspicious activity. It takes snapshots of system files and compares them to previous versions, sending an alert if any changes are found. This is commonly used for mission-critical applications and devices that are not expected to change.
- Protocol-based intrusion detection system
PIDS is a system or agent placed at the front of a server to monitor and interpret the protocol between a user or device and the server. It secures the web server by consistently monitoring the HTTPS protocol stream and handling the related HTTP traffic. Since HTTPS is unencrypted before entering the web presentation layer, PIDS operates in this interface to ensure security.
- Application-protocol-based intrusion detection system
It detects intrusions by monitoring and analyzing communication on specific application protocols. For example, it tracks SQL protocol activity as it interacts with the database on a web server.
While understanding the types of IDS is critical for robust network security, it’s equally crucial to be aware of the stealth techniques that attackers use to evade these systems, undermining their effectiveness.
IDS Evasion Techniques
Understanding threat actors’ evasion techniques to breach secure networks helps IT departments recognize how IDS systems can be tricked into missing real cyber threats.
- Fragmentation
Sending fragmented packets allows attackers to evade detection by slipping past the system’s ability to identify attack signatures.
- Low-bandwidth attacks
Coordinating a scan across multiple attackers or assigning different ports or hosts to each attacker complicates the ability of intrusion detection system algorithm to correlate packets and detect an ongoing network scan.
- Address spoofing
Attackers can conceal the attack’s origin by routing it through poorly secured or misconfigured proxy servers. When the source is spoofed and bounced off a server, tracing the origin becomes gruesome.
- Pattern change evasion
IDS systems depend on pattern matching to identify attacks. Slight modifications to the attack structure can help evade detection.
In the evolving cybersecurity landscape, differentiating between IDS and Intrusion Prevention Systems (IPS) is vital for deploying an effective defense strategy tailored to an organization’s specific security needs.
IDS Vs. IPS: Major Security Nuances
Distinguishing between various intrusion monitoring systems is essential for crafting a robust defense strategy against evolving threats.
IDS in Tandem with Other Security Solutions
IDS is not a standalone security solution; it’s intended to function within a comprehensive cybersecurity framework, often closely integrated with various other security measures.
- IDS and SIEM (security information and event management)
IDS alerts are typically routed to an organization’s SIEM, where they are consolidated with data from other security tools into a unified dashboard. Integrating SIEMs with IDS enables security teams to trigger warnings with threat intelligence and risk management, prioritize incidents for remediation, and filter out false positives.
- IDS and firewalls
IDSs and firewalls work together to enhance security. Firewalls positioned at the network’s perimeter use predefined rules to control traffic flow. IDSs are typically placed near firewalls to detect any threats that bypass them. Many next-generation firewalls even include built-in IDS and IPS capabilities.
- IDS and IPS
Some organizations deploy IDS and IPS as separate solutions, but it’s more common to integrate them into a single Intrusion Detection and Prevention System (IDPS). This combined system detects intrusions, logs them, alerts security teams, and automatically responds to threats.
Concluding Lines
An intrusion detection system architecture is a vital tool for businesses aiming to protect their networks from unauthorized access. An IDS detects suspicious activities with network traffic analysis and alerts system administrators about potential threats. Beyond just security, an IDS enhances an organization’s overall network performance by providing valuable insights into traffic behaviors. Integrating IDS into a company’s security infrastructure significantly strengthens its defense mechanisms and helps maintain a robust, secure network environment.
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