SIEM vs. IDS: Understanding the Core Differences

SIEM vs IDS are great solutions for enhancing cyber security defenses within organizations and taking preventive action. Choose the tool that best fits your organization by learning about their differences. and see how you can incorporate them for best results.
By SentinelOne August 16, 2024

A SIEM center collects, reviews, and analyzes security logs and tracks all kinds of security events and incidents. It is a solution meant to help IT personnel discover the presence of any possible threat or attack before they are actually launched. Current SIEM tools nowadays use Machine Learning and Artificial Intelligence algorithms for detecting anomalies as well as malicious behavior patterns in data storage and management.

The objective of an SIEM is to be compliant with the latest industry regulations and provide organizations with the requisite threat intelligence to have adequate cyber protection. IDS is used for monitoring network activities and defines a security baseline to detect and prevent security intrusions. SIEM and IDS both should be used in conjunction as that would give the best results but there are significant differences between them and each has its own specific use cases.

SIEM vs IDS? In this post, we’re going to uncover the main differences between SIEM and IDS, and equip you with all the knowledge needed to start working with them.

SIEM vs IDS - Featured Image | SentinelOneSIEM vs IDS: Understanding the Differences

A survey conducted by Cybersecurity Ventures revealed that 63% of enterprises use SIEM tools, while 44% use IDS tools. From small and mid-sized to large organizations, enterprises are widely accepting SIEM solutions as it help in automating their security process flows. Next-gen SIEM solutions come integrated with powerful Security Orchestration, Automation and Response (SOAR) capabilities thereby reducing costs & efforts for IT teams. These tools utilize deep machine learning algorithms for advanced threat detection, incident response, and analysis.

IDS systems are network-based and can identify threats in real time. SIEM systems usually rely on logs from a variety of sources, which can cause a lack of visibility for network traffic. SIEM solutions work with rule-based detection, which is less effective than with IDS where anomalies in traffic are detected.

What is SIEM?

Original SIEM tools in the past were traditionally log management solutions that were restricted to collecting security logs. Modern SIEM combines security log collection with security event management functions. They enable real-time threat monitoring and analysis of various security-related events.

Recent innovations in SIEM technologies have incorporated User and Entity Behavior Analytics (UEBA). The SIEM of today is becoming the de-facto for new-age Security Operations Centers (SOCs) and has dramatically improved most of the security monitoring and compliance management use cases. SIEM, at a basic level, aggregates & even correlates logs to security threats and ensures that they satisfy compliance. Most of these tools support integrations with other tools which can also give automated reports to the users.

What is IDS?

It is important to note that IDS doesn’t do anything to prevent intrusions or threats. IDS solutions simply notify the staff when malicious activities or patterns exceed certain baselines. It only monitors security systems and sends automatic notifications. IDS is a tool that is used to monitor everyday activities and sets new benchmarks based on analyst feedback. An IDS solution can pass the data collected by it to a SIEM for further threat analysis.

5 Critical Difference between SIEM and IDS

#1 – SIEM offers organizations a solution that includes the collection, monitoring, and analysis of security-related data from many sources, which will aid in identifying potential security threats. IDS detects and alerts potential security threats in real time. Its major role leans toward the analysis of network traffic.

#2 – SIEM involves advanced analytics in the form of correlation, anomaly detection, and analysis using machine learning models to detect any possibility of threats. IDS depends only on rule-based detection and signature matching to identify known threats.

#3 – SIEM allows real-time alerts and the ability to respond to incidents, thereby equipping security systems with due actions against threats. IDS will provide alerts about potential threats but will often require investigation and a manual response.

#4 – SIEM can store huge volumes of data to identify trends and analyze threats. IDS solutions have the problem of limited data storage capacity, which means they’re not ideal for long-term data retention.

#5 – You can detect and remediate zero-days, ransomware, malware, advanced persistent threats (APTs), and insider attacks with SIEM systems. IDS generates high volumes of false positives due to its reliance on rule-based detection and signature matching.

SIEM vs. IDS: Key Differences

Feature SIEM (Security Information and Event Management) IDS (Intrusion Detection System)
Log Collection Collects and analyzes log data from various sources, including Network devices (firewalls, routers, switches),  Servers (Windows, Linux, Unix), Applications (web, database, email),  Cloud services (AWS, Azure, Google Cloud), Endpoints (workstations, laptops, mobile devices) Typically collects log data from network devices and systems, including Network devices (firewalls, routers, switches), Servers (Windows, Linux, Unix), Network protocols (TCP/IP, DNS, HTTP)
Threat Detection Detects advanced threats, including Insider threats, Advanced Persistent Threats (APTs), Zero-day attacks,  Malware,  Ransomware, Fileless malware, Lateral movement Detects known threats and attacks, including Malware, Viruses, Unauthorized access, Denial of Service (DoS) attacks, Distributed Denial of Service (DDoS) attacks
Alerting and Response Provides real-time alerting and incident response capabilities, including Automated alerting to security teams and incident responders, Prioritization of alerts based on severity and impact, Integration with incident response tools and playbooks Provides real-time monitoring and alerting, but may not always trigger alerts. Manual response is required, relying on human analysts
Anomaly Detection Uses machine learning and behavioral analysis to detect anomalies and unknown threats Typically uses signature-based detection, relying on known attack patterns
Network Traffic Analysis Analyzes network traffic to detect suspicious activity, including Network protocol analysis (TCP/IP, DNS, HTTP), Network flow analysis (NetFlow, sFlow), Packet capture and analysis Analyzes network traffic to detect suspicious activity, including Network protocol analysis (TCP/IP, DNS, HTTP), Network flow analysis (NetFlow, sFlow)
Endpoint Detection Detects and responds to endpoint-based threats, including Malware, Ransomware,  Fileless malware, Lateral movement Typically focused on network-based detection, but may have some endpoint detection capabilities
Cloud Security Essential for cloud security, as it can collect and analyze log data from cloud-based services and applications Can be used in cloud environments, but may require additional configuration
Compliance Helps organizations meet compliance requirements by providing a centralized platform for log collection, analysis, and reporting Not specifically designed for compliance, but can provide some compliance-related features
Cost Typically more expensive than IDS, due to the complexity and scalability of SIEM systems Generally less expensive than SIEM, due to its focused scope and simpler architecture
Scalability Designed to handle large volumes of log data and scale to meet the needs of large organizations Typically designed for smaller to medium-sized networks and may not scale as well as SIEM systems
Integration Integrates with a wide range of security tools and systems, including Firewalls, IDS/IPS systems, Endpoint security solutions, Cloud security solutions Typically integrates with other security tools and systems, but may have limited integration options compared to SIEM systems

SIEM vs IDS: Integration and Function

The main difference between SIEM and IDS is that SIEM can take preventive action against cyber security threats while IDS simply detects and reports events. The good news is, you can combine them to build a robust cyber defense strategy. SIEM technology gives security analysts a holistic view of their infrastructure and can centralize logs and events.

The core components of SIEM include:

  • Support for open-source threat intelligence feeds
  • Compliance and security incident management
  • Log collection and event management
  • Analyze events and data from multiple sources
  • Improved digital forensics

IDS is preferable when it comes to identifying undesirable behavioral patterns in networks. It can monitor security systems and scan them for potential policy violations. IDS can use signature-based detection methods to identify threats with known characteristics. It can easily analyze malicious code but might find it difficult to address newer forms of threats. Fortunately, IDS has other threat identification modes. By assigning reputation scores, IDS can distinguish between different threats. It can leverage anomaly-based detection to uncover unknown attacks and find new malware strains. IDS models can be trained on enterprise networks’ specific data and also provide SOC teams with alerts for anomaly detection events.

IDS can be used to store event log information but it cannot correlate and consolidate them into a unified platform. IDS can complement SIEM by giving it packet-level inspection capabilities. When you combine both SIEM and IDS, you can effectively detect and prevent unauthorized access to sensitive information. The incident response team can use IDS to collect the raw data from different sources and use SIEM to centralize and analyze it

Together, they can establish tickets, prevent IPs, and assist in secluding the systems that have been impacted. Well-coordinated and trained security experts can prevent security breaches and privilege escalations by leveraging these two innovations. With the help of IDS, users can enrich SIEM’s datasets for specific detection events and perform custom packet analysis.

SIEM vs IDS: Use Cases

Intrusion Detection Systems (IDS) are very easy to set up and require minimal configuration changes. Organizations of all sizes can implement them as a part of their cyber defense strategy at any phase of the threat mitigation lifecycle.

However, a key challenge is fine-tuning IDS solutions and making them sensitive to specific requirements.

SIEM solutions have more advanced configurations and require significant time for installation. Since they integrate data from multiple sources for event correlation, analysis, and alerting their complexity increases. SIEM tools are easy to maintain, however, organizations need to constantly refine correlation rules and analytics to improve threat identification accuracy and eliminate false positives.

Follow are the use cases of SIEM vs IDS:

  • SIEMs provide an organization-wide centralized platform for log collection, analysis, and reporting thus enabling compliance with regulatory requirements. They can detect sophisticated attacks like insider threats, APTs or even zero-day attacks through the analysis of log data from several sources. Network-based threats such as malware, viruses, or unauthorized access are detected and notified by IDS systems.
  • In addition to real-time alerting and monitoring that enables fast incident response and mitigation, SIEMs also offer anomaly detection using advanced analytics and machine learning capabilities. On the other hand, IDSs employ signature-based methods that identify known threats.

Here are some differences in how SIEM vs IDS operates:

  • On cloud security compliance, SIEMs collect and analyze log data thereby enhancing information security because they can be collected from various sources on cloud-based applications or services. IDSs generally deployed at the edge of a network can detect potential hackers before they establish a connection with the inside of an organization.
  • Monitoring network traffic flow about increasingly common anomalies like DDoS attacks or lateral movement is among some functionalities performed by SIEM systems while IDSs may be employed within certain segments of a given local area network (LAN) as a means of monitoring any indication that may represent possible intrusion attempts.
  • SIEM systems collect and analyze endpoint log data to detect and respond to endpoint-based threats. They monitor identity and access management systems to detect and respond to identity-related threats. IDS systems can detect and alert on wireless-based threats, such as rogue access points and unauthorized wireless access.

Consolidating SIEM & IDS for Better Cybersecurity

SIEM solutions will enable organizations with radical clarity and empower organizations with high-fidelity threat detection and response features. We can expect security analysts and operations teams to get next-gen analytics at their fingertips and enhanced visibility like never before. IDS and SIEM combined will provide holistic security perspectives on organizational infrastructures. They will seal gaps in security, address vulnerabilities, and eradicate real-time threats by incorporating the best cyber hygiene practices.

Next-gen SIEM and IDS integrations will inform users about other entities that may be potentially impacted during security events. Combined with federated search, these two innovations will break down operational silos, enhance compliance, and reduce storage costs. Users will be able to quantify risks across their IT and cloud estates in real time and focus on what matters the most, regardless of data sources.

Conclusion

Choose SIEM when you require comprehensive detection and responsive security monitoring. SIEM can do way more advanced threat detection and provides the possibility for incident response. However, SIEM is very well targeted towards your log collection, analysis, and regulatory compliance if that is what you are looking for.

Otherwise, if your focus is mainly on network-based threats and you require a solution that can detect those threats in real time. IDS will work best because it offers this feature which makes it one of the most efficient solutions for network-based attacks. IDS is also helpful for organizations with a smaller budget since it is relatively inexpensive. There are low rates of false positives associated with IDS to minimize noise and improve incident response too.

You should consider both SIEM and IDS to achieve comprehensive security monitoring as well as network-based threat detection benefits simultaneously. You can make your security posture more robust by integrating them.

Ultimately, whether you go for IDS vs SIEM depends on what kind of protection your organization needs; its infrastructure, budgets, etc. Therefore, look at all your needs carefully before revamping your existing security strategy and combine the services of both these products for the best security monitoring and performance.

SIEM vs IDS FAQs

1. Can SIEM replace IDS or vice versa?

While SIEM and IDS share some similarities in functionality, they were designed for different purposes and thus cannot be completely replaced by each other. A SIEM can take the place of an IDS in part but not totally. An IDS gives real-time analysis of network traffic and detection of known threats, and SIEM is different in that aspect.

2. What is the difference between IAM and SIEM?

IAM and SIEM are two very different security solutions, both serving two different purposes: IAM for digital identity and access management, and SIEM for monitoring and analysis of security-related data in the detection and response against security threats.

3. Is SIEM a threat intelligence platform?

SIEM and Threat Intelligence Platforms are two independent security products that do different things. While SIEM might have some threat intelligence features, this does not mean it can outperform the traditional TIP. One of the main aspects to be emphasized here is that typically, SIEM monitors and analyzes security-related data from an organization’s interior, while TIP handles collecting and analyzing threat-related data arising from open-source intelligence, commercial feeds, and internal sources.

4. What is the difference between SIEM vs IDS vs IPS?

IDS and IPS remain firmly positioned at the front door, screening the visitor list, and weeding out trespassers. SIEM takes all information from the IDS, IPS, logs, and firewalls to create a complete security picture of the network and acts on it— going beyond filtering hostile traffic. IPS and IDS can be considered as unified threat managers that monitor, control, and block suspicious network traffic. SIEM provides centralized views that enable organizations to detect and remediate complex threats via data threat data analysis from multiple sources and diverse formats.

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