Suricata is an open-source Intrusion Prevention System (IPS) and Intrusion Detection System (IDS) solution. It gives you the ability to focus on detection capability, helping you achieve complete visibility of your network. The need for Suricata arises majorly from two things: threat detection and visibility.
When you deploy solutions like antivirus or firewall solutions, you completely rely on those solutions. For example, if you install a firewall, antivirus, anti-phishing, or email filtering solution, these are primarily prevention techniques. This means that when you deploy them, you often forget about them, letting the software take action automatically. You don't get complete visibility into everything happening. If your firewall or antivirus itself gets bypassed by advanced malware, you might never know about it. Therefore, you need to be very focused on detection capability. However, this requires some human intervention to look at packets, perform initial triage, and remove false positives, as deploying IDS or IPS solutions can often lead to encountering quite a lot of false positives.
A common question is the difference between IDS and IPS. IDS stands for Intrusion Detection System, and IPS stands for Intrusion Prevention System. Suricata can be deployed in both modes. An IDS detects intrusions, like anomalous behavior, threats, or suspicious activity within the network, and reports it to an administrator who then takes action. On the other hand, an IPS detects the threat and can also take action itself, hence the name Intrusion Prevention System. You might wonder why someone would opt for IDS if IPS can automatically prevent threats. The reason is that using IPS straight away might disrupt business operations. As mentioned, false positives or other issues could hamper business-critical applications. Often, organizations start with IDS mode, tune the system, and then move to IPS, or sometimes use a mix-and-match approach.
Ultimately, you need complete visibility into your network environment and the ability to detect suspicious activities and threats. These are the primary reasons why Suricata is valuable.
Key Features
Signature-Based Detection
Suricata utilizes rulesets for detection. You can create custom rules, and it also benefits from extensive inbuilt rules provided by sources like Emerging Threats (now Proofpoint ET Intelligence), which offers free rulesets.
Anomaly-Based Detection
It can detect suspicious traffic patterns that deviate from the norm. For example, a sudden significant rise in traffic for a specific user could be flagged. It also examines protocol details, like unusual User-Agent strings in HTTP traffic (e.g., "random 123" instead of a standard browser name like Chrome or Mozilla), which could indicate suspicious activity.
Multi-Threading Support
Suricata is designed for high performance and can process a large volume of network data efficiently due to its multi-threaded architecture, making it very powerful.
Protocol Support
It supports a wide array of protocols, including TCP, UDP, ICMP, HTTP, SMTP, FTP, DNS, TLS, SMB, and many more, allowing for comprehensive traffic analysis.
Rule Customization
Users have the option to create and customize their own detection rules, tailoring Suricata to their specific environment and threat landscape. Suricata rules look deeply into traffic, examining headers and potentially payload content, going beyond traditional firewall rules based solely on source/destination IP and port.
Pros and Cons
- ✅ Completely free and open-source (maintained by OISF).
- ✅ Powerful threat detection capabilities (signature and anomaly-based).
- ✅ Provides deep network visibility.
- ✅ High performance due to multi-threading.
- ✅ Flexible deployment options (IDS or IPS mode).
- ✅ Supports a wide range of protocols and custom rules.
- ❌ Requires human intervention for analysis and tuning.
- ❌ Can generate a significant number of false positives initially.
- ❌ Configuration and rule management can be complex.
- ❌ Setting up in IPS mode requires careful consideration to avoid disrupting legitimate traffic.
Practical Use Cases
Suricata is widely used for:
- Network Security Monitoring (NSM): Gaining visibility and detecting threats across the network.
- Incident Response: Providing detailed logs and alerts to aid in investigating security incidents. When deployed in IPS mode, it can automatically block malicious traffic.
- Threat Hunting: Enabling security analysts to proactively search for signs of compromise or suspicious activity within network traffic logs.
Availability and Download
Suricata is a completely free, open-source software maintained by the Open Information Security Foundation (OISF). Unlike some other security tools that may have community and paid versions (like Snort, which is associated with Cisco), Suricata remains fully free. You can download the latest version and find documentation on the official Suricata website.
