An Intrusion Detection System (IDS) is for protecting networks and data from unauthorised access and attacks. It monitors network traffic to identify malicious activities and potential threats. IDS can detect both external and internal threats, ensuring a secure environment for organisations.
An effective IDS acts as a security sentinel, alerting administrators about suspicious activities before they escalate into serious breaches.
What is an Intrusion Detection System (IDS)?
An Intrusion Prevention System (IPS) is a security tool that not only detects suspicious or malicious activity in network traffic, but also actively prevents it by blocking, rejecting, or mitigating the threat in real time.
What is the difference between an IDS and an IPS?
The key difference between an IDS and IPS is their functionality. An IDS focuses on detection and alerting, leaving response actions to security teams. An IPS, on the other hand, takes immediate action to stop detected threats.
How IDS Works
An IDS operates through several key processes:
- Data Collection: The system gathers data from various sources, including routers, firewalls, and servers.
- Traffic Analysis: It analyses incoming and outgoing traffic patterns to identify anomalies.
- Alert Generation: When suspicious activity is detected, alerts are sent to administrators for further investigation.
- Response Coordination: In an IPS, and depending on the configuration, the IDS can initiate predefined responses to mitigate threats.
Types of Intrusion Detection Systems
There are two main types of IDS:
- Network IDS / IPS (NIDS / NIPS): This type monitors network traffic for suspicious activities across the entire network. It is suitable for large environments with multiple entry points, providing a holistic view of the network.
- Host IDS / IPS (HIDS / HIPS): Installed on individual devices, HIDS monitors the internal activities of the host. It provides a detailed analysis of processes, file integrity, and user behaviour, allowing for targeted security measures.
What types of threats can IDS detect?
Network IDS/IPS defends against various attack techniques, such as:
- Denial-of-Service (DoS / DDoS): Protecting against malicious network overloads that can disrupt services and cause outages.
- Network Scanning: Identifying a threat actor’s “probing” for open ports and services can help detect an attack in its early stage.
- Malware Distribution: Identifying malicious payloads in network traffic.
- Man-in-the-Middle Attacks: Intercepting and modifying network communication.
- Worms and Virus Propagation: Detecting malware spreading across the network.
- Lateral Movement: Detecting unauthorised movements of a threat actor within a network, thus limiting the scope / scale of an attack.
- Command-and-Control (C2) Communication: Identifying traffic between compromised devices and attacker-controlled servers.
- Data Exfiltration: Detecting unauthorised data transfer from the network.
Host-based IDS / IPS focus on protecting individual devices from threats such as:
- Privilege Escalation: Preventing unauthorised access to sensitive system resources.
- File Integrity Changes: Detecting unauthorised file changes or tampering.
- Malicious Code Execution: Blocking malware or harmful scripts at the host level.
- Unauthorised Access: Monitoring login attempts or configuration changes.
- Keylogging and Credential Theft: Identifying attempts to capture sensitive keystrokes or user credentials.
- System Configuration Changes: Alerting on unauthorised modifications to system settings or registry.
IDS Evasion Techniques
Cybercriminals use various techniques to evade detection by IDS. Understanding these methods can help enhance security measures. Common evasion techniques include:
- Traffic Fragmentation: Attackers break malicious payloads into smaller packets, making them difficult to detect.
- Protocol Tunnelling: This involves hiding malicious traffic within legitimate protocols, such as HTTP or DNS.
- Polymorphic Code: Attackers modify their code frequently to avoid signature detection by the IDS.
What Makes a Good Intrusion Detection System (IDS) / or Intrusion Prevention System (IPS)?
When choosing an IDS / IPS, consider the following:
- Detection Accuracy: Minimal false positives and negatives to ensure effective threat identification without alert fatigue.
- Behavioural Analysis: The best IDS / IPS systems utilise machine learning to learn the behaviours of your network or devices. After learning what “normal” is, they can better detect unusual and potentially harmful activity in the network or on the device.
- Threat Intelligence: Regular updates with the latest threat signatures and behavior patterns.
- Integrations: Compatibility with existing security tools and systems, including threat intelligence solutions which can improve detection rate.
- Real-time response: For IPS, ensure it can block threats instantly without disrupting legitimate traffic.
- Performance: You must ensure that your IDS / IPS has minimal impact on your network system or performance.
Incorporating a secure IDS into your cybersecurity strategy can significantly lower the risks of breaches and improve your overall security. By understanding the types of IDS and potential evasion techniques, organisations can better defend against evolving threats.
If you want to protect your business against cyber threats, then get in touch and see how our cyber insurance services can help you.
