SIEM vs XDR: Capabilities and Key Differences

Cloud Security Misconceptions

All enterprises comprise vast webs of interconnected devices. An average company relies on hundreds of thousands of endpoint devices at any one time. The constant exchange of information necessary to sustain business depends on a network of surrounding infrastructure, such as load balancers, data storage, and APIs.

As network sizes increase, so too does the data infrastructure that support them. The sheer amount and variety of reliant devices and networks create more opportunity for bad actors to infiltrate an organization’s network.

This article will compare two SOC technologies — security information and event management (SIEM) and extended detection and response (XDR) — to see how each streamlines information processing.

What is SIEM and How Does it Work?

SIEM solutions use logs to maintain insight into a complex network of devices, firewalls, and switches. Logs contain information about a server’s internal workings. SIEM applications were the first to give security teams deeper insight into application health. Since 2005, SIEM has evolved rapidly; modern offerings aggregate and analyze log data in near real time. As a result, well-configured SIEMs use rules to cut through the noise of endless logs and alert security administrators to significant events. For more info, see our guide, What is SIEM?

By combining correlation rules and models, SIEM transforms data into action. Correlation rules simply tell your SIEM system what sequence of events could indicate an attack, and to notify your admin team when something doesn’t seem right.

All sorts of behavior can trigger individual rules. Composite rules analyze concerning behaviors by chaining multiple rules together. For example, your SIEM can flag 6 failed login attempts from the same IP address — but only if that IP address is trying with 6 different usernames.

An advanced SIEM tools profiles normal data traffic patterns; with composite rules, it triggers an alert if suspicious behavior pops up — such as a user switching from their normal account to a privileged one, then attempting to perform an abnormal data transfer to or from an external service. Modern SIEM platforms use data visualizations to provide a unified view of threats across most of your organization’s technology stack.

What is XDR? How Does it Work?

While SIEM tools have provided security professionals with unparalleled log visibility, many systems are incompatible with the SIEM tool. The rule-based approach also leaves security teams swamped with unimportant alerts.

An XDR solution, however, comprises several security concepts, using data from endpoints, email systems, networks, IoT devices, and applications to expand the scope of security events. Whereas endpoint detection and response (EDR) systems rely on siloed traditional security measures, XDR integrates the log management approach of SIEM with a number of other security components to form a cohesive whole. Integrating EDR systems within XDR extends visibility into every endpoint. XDR incorporates network traffic analysis to identify even the most advanced attack patterns.

Cloud security tools are another crucial integration point for XDR systems. Integrating cloud access security brokers (CASBs) and secure web gateways into the XDR ecosystem monitors and protects cloud environments. XDR’s scope can be as wide as necessary: integrating identity and access management (IAM) solutions further provides insight into user behaviors and access patterns, to prevent identity-based attacks.

An analysis engine uses telemetry data to determine the nature of every alert. After identifying a potential threat, XDR platforms can automatically respond by isolating affected systems, blocking malicious activity, rolling back actions to a safe state, or alerting the security team. With its increased visibility, XDR provides a promising foundation for automated security responses.

These automated playbooks synthesize responses based on severity, drastically reducing response time and alert backlogs. XDR creates a comprehensive cross-department information that drastically streamlines an analyst’s task, allowing them to work more strategically and effectively. If you’re still left asking ‘What is XDR?’ see our deep dive into this new and exciting field.

SIEM vs XDR Comparison: 5 Key Differences

The differences between SIEM and XDR solutions are nuanced but important. SIEM offers a way to collect and store logs for compliance, data storage and analysis. Traditional SIEM solutions bolt security analytics on top of existing log collection and normalization features. Without a native ability to distinguish between genuine threats and false alarms, security teams are often overwhelmed.

XDR, on the other hand, is built specifically for threat identification and to accommodate the gaps in SIEM logs. It centralizes endpoint and firewall data, rather than raw logs alone. While XDR offers organizations new security capabilities and enhanced protection, SIEM still has vital use cases outside of threat detection, such as log management and compliance.

The following table offers an in-depth XDR vs SIEM comparison.

Data SourceLog files that comprise events from a series of devices.Endpoints, firewalls, servers, and other security tooling — including SIEM.
Deployment LocationData collected via data center with a dedicated SIEM appliance.  Agents on each endpoint and network appliance. Central depository is within own architecture, using vendor threat intelligence.
Deployment ModelStorage systems require manual maintenance. Pre-integration with cloud systems and data sources allows for quicker deployment.Automated in-house threat detection teams identify emerging threats. Manual security ops address the highest-priority threats.
Performance and Storage ConsiderationsNo negative performance impact. Large quantity of logs - storage required between 1 and 7 years. Syslog servers retain only essential information in a standardized format.When monitoring east-west traffic, performance can be impacted. Depending on the organization's size, a data lake may be required for telemetry data.  
Fundamental ApproachEnables organizations to scrutinize log data from all network applications and hardware at any time.Streamlines the collection, analysis, and remediation across the full spectrum of an organization’s security tools.

SIEM Pros and Cons

SIEM is ultimately only a log-focused approach to security. While it can accelerate incident detection, its intense resource demands can be overwhelming. While many organizations still depend on SIEM, Stellar Cyber’s Next-Gen SIEM Platform combats many of its significant downsides.


Faster Than Manual Log Management

Effectively deployed, SIEM reduces the timeframe for detecting and recognizing threats, enhancing your capacity to respond swiftly and mitigate damage. SIEM’s adaptability helps identify elusive zero day threats that might bypass conventional security measures.

Strong All Rounder

SIEM serves a broad spectrum of uses throughout your organization, ranging from operational support to troubleshooting. It equips IT teams with essential data and historical logs, enhancing their efficiency and effectiveness in managing and troubleshooting issues outside of cybersecurity alone.


The Struggle of Real-Time Reporting

SIEM is severely limited by time-related issues, like synchronization and processing. Even if reports are generated quickly, the response time for an analyst to react to an alert creates a significant delay.

Fine-tuning Demands Full-Time Support

SIEM systems rely on constant updates, which require full-time support teams. These security staff are solely focused on keeping the SIEM tool running well rather than actively analyzing and triaging alerts.

Distinguishing genuine incidents from meaningless would be nearly impossible if a system input all alerts into the SIEM. Without a method to sort incidents, any system would be overwhelmed with inputs.


In most cases, SIEM tools don’t communicate with other security tools in your stack. Your security team needs to manually compare alerts across different dashboards and tools. Therefore, all processes downstream of a SIEM report demand considerable technical expertise. Parsing out essential information is still critical.

XDR Pros and Cons

As cyber threats increase, XDR’s integrated approach gets more appealing. Implementing XDR means understanding its pros and cons, potential complexities, and resource requirements. This comparison equips cybersecurity professionals and enthusiasts with a clearer understanding of XDR's benefits.

XDR Pros

Extended Detection

XDR coalesces security data into smaller, high-fidelity incident alerts. The wider scope of telemetry data - and the enhanced understanding of interconnected systems makes it more likely that your team can find an active threat. Of course, collecting data is only the beginning.

Extended Analysis

An XDR system delivers analysis essential to address incidents: is this a genuine threat or a false alarm? Does it signify a more significant risk? If so, to what extent? Cyberattacks can disguise their initial signs, rendering them harder to detect; XDR platforms can protect organizations from attacks without traditional signs.

XDR Cons

Vendor Lock-In

Today’s cybersecurity market is still holding back many XDR tools’ potential. Vendors that specialize in specific security tooling are currently the ones offering vendor-locked XDR. As a result, the additional security demands of an XDR are rapidly developed and bolted on. For organizations that aren’t as experienced with certain capabilities, security teams end up with a flawed toolkit that performs worse than a basic SIEM.

Avoid Lock-In And Unlock Full Security Comprehension

Stellar Cyber's Open XDR platform proactively detects, investigates, and responds to threats across an entire digital ecosystem. With its scalable architecture, the platform seamlessly aggregates data from various security tools, providing comprehensive insights into potential security threats. Explore Stellar Cyber’s Open XDR Platform today.

Guest blog courtesy of Stellar Cyber. Read more Stellar Cyber guest blogs and news here. Regularly contributed guest blogs are part of MSSP Alert’s sponsorship program.