One cannot compare Suricata vs Zeek without also comparing these tools to the popular Snort. While we believe Suricata stands out above the competition, it is still valuable to understand the differences in Zeek and Snort to make the most informed decision when selecting an open-source intrusion detection tool. This blog post provides a basic introduction to open-source intrusion detection and provides details on Suricata, Snort, and Zeek, ultimately crowning one open-source intrusion detection tool as the victor.
What is open-source intrusion detection?
Open-source intrusion detection tools (abbreviated as IDS) are security software systems that monitor an organization’s network for malicious activity and that are freely available for anyone to use, modify, and distribute. Instead of relying on pre-built commercial security software, open-source intrusion detection tools offer a different approach based on transparency, flexibility, customizability, and community collaboration.
The core idea is that the IDS’s code is open for anyone to download, use, alter, and improve. This openness allows for a wide range of individuals to contribute to its development while also tailoring the system for their own unique needs. The rules used by the IDS are also commonly shared in various threat intelligence sharing platforms, enabling users to support each other and stay up to date with new and emerging threats.
Open-source intrusion detection tools are an incredibly cost-effective option for many organizations because they eliminate the licensing costs associated with commercial security software, making it an attractive option for personal use or budget-conscious organizations.
What is Suricata used for?
Suricata is used to provide network security support by identifying or blocking malicious traffic entering the network. Whether it is used in IDS or IPS mode, Suricata’s purpose is to provide a layer of defense using:
- Threat Detection: Suricata constantly examines network traffic for malicious patterns. It compares this traffic to a vast database of known attack signatures and pre-defined Suricata rules. These signatures are like the fingerprints of specific threats, allowing Suricata to identify malware, exploit attempts, and suspicious network activity.
- Deep Packet Inspection: Suricata inspects data packets, analyzing not just the source and destination, but also the content itself. This allows it to detect hidden threats within encrypted traffic or files being transferred.
- Protocol Analysis: Suricata can analyze a wide range of network protocols, understanding how different types of communication work. This lets it identify suspicious behavior within specific protocols, like unusual data transfers or attempts to exploit vulnerabilities in certain communication methods.
- Network Traffic Baselining: Suricata can be used to establish a baseline of what "normal" traffic looks like on your network. By monitoring activity over time, a machine learning engine can use the data produced by Suricata to learn the typical patterns and identify significant deviations that might indicate a potential attack.
- Threat Hunting: Suricata's detailed logs and analysis capabilities are valuable for security professionals. They can use Suricata's data to investigate suspicious activity, identify trends, and proactively hunt for hidden threats within the network.
What is the difference between Snort and Zeek?
Snort and Zeek are both popular open-source intrusion detection tools, but it is important to understand that they have key differences in what they detect, how they detect it, and how easy (or difficult) they are to use. Let’s look at both tools:
- Snort: Snort functions as a signature-based Intrusion Detection System (IDS) or Intrusion Prevention System (IPS). It inspects network traffic for predefined patterns that match known malicious activity. These patterns are expressed as signatures within a rule set. Upon detection of a matching signature, Snort can be configured to trigger pre-defined actions such as raising alerts or blocking the identified traffic.
- Zeek: Zeek, formerly known as Bro, operates as a network traffic analyzer. While it has security applications, it's not a dedicated IDS. Zeek captures and performs deep analysis of all network traffic. This analysis allows security personnel to identify suspicious activity through the development and implementation of custom scripts. Zeek offers a more flexible approach to network traffic investigation but requires a higher level of expertise for configuration and result interpretation.
Key Differentiators:
- Detection Method: Snort relies on pre-defined signatures for detection, while Zeek utilizes custom scripts to identify anomalies within the captured traffic data.
- Analysis Depth: Snort primarily focuses on the network layer for traffic inspection. Zeek offers multi-layered analysis capabilities, extending to the application layer for a more comprehensive view.
- Ease of Use: Snort is generally easier to set up and use due to its pre-defined rule sets. Zeek requires a higher level of expertise due to the need for custom scripting and analysis of the captured data.
Which is better? Snort, Suricata, or Zeek?
In the battle between Zeek vs Suricata vs Snort, Suricata reigns supreme. There are several reasons why this is the case:
- Superior Performance:
- Multi-threading: Unlike Snort, which is single-threaded and limited by a single CPU core, Suricata is natively multi-threaded. This allows it to leverage multiple cores on modern processors, significantly improving its ability to handle high-volume network traffic. This efficiency is crucial for modern networks where traffic volume is constantly increasing.
- Resource Efficiency: Tests have shown that Suricata can achieve the same detection accuracy as Snort while consuming fewer resources. This translates to lower overhead on your system, allowing it to dedicate more resources to other critical tasks.
- Deeper Network Visibility:
- Network Security Monitoring (NSM): Suricata goes beyond basic IDS functionality. It can also function as a valuable NSM tool, capturing and analyzing detailed network traffic information. This comprehensive data can be used for broader security investigations and network troubleshooting.
- Application Layer Inspection: In addition to network layer inspection, Suricata can delve deeper and analyze application layer protocols. This allows it to detect more sophisticated attacks that might bypass traditional signature-based detection. Zeek can perform this type of inspection, but it lacks signature-based detection capabilities.
- Flexibility:
- Snort Rule Compatibility: Suricata can leverage existing Snort rule sets, making migration from Snort a smoother process. This compatibility allows you to benefit from the vast Snort community and its extensive rule base.
In conclusion, Suricata combines the strengths of both Snort and Zeek with a multi-threaded architecture, deeper network inspection capabilities, and the ability to function as an NSM tool. This combination translates to more efficient use of system resources, improved detection accuracy for modern threats, and broader network security insights. For a high-performance, adaptable, and efficient open-source IDS solution, Suricata stands out as a compelling choice.
Learn More About Suricata
To begin learning more about Suricata, we recommend downloading the open-source book published by Stamus Networks titled “The Security Analyst’s Guide to Suricata” — the first practical guide to threat detection and hunting using Suricata, the world’s most popular open-source network security engine.
Written for security operations center (SOC) analysts and threat hunters who use Suricata to gain insights into what is taking place on their networks, the book provides vital information on entry points and an in-depth analysis of the most important Suricata features.
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