Anomaly Detection

What is Anomaly Detection?

Anomaly detection within AI-driven monitoring automatically identifies deviations from normal patterns, detecting potential security threats, system failures, performance slowdowns, or cyber risks in real-time. Good, automated anomaly detection enables proactive incident response and risk mitigation.

Automated anomaly detection is now a key functionality in many regulated sectors for ICT and IT compliance. Many standards, regulatory frameworks and directives now mandate that anomaly detection should be used to automate operational resilience, cybersecurity monitoring, and threat intelligence. For example, in the EU, the Digital Operational Resilience Act (DORA) mandates organizations to implement anomaly detection as outlined in Article 10 (“Detection”), and requires entities to identify potential risks and threats that could compromise operational resilience. Learn more: What is the Digital Operational Resilience Act (DORA)? Everything you need to know about DORA compliance | eG Innovations.


The Role of Baselines in IT Monitoring Anomaly Detection

In IT monitoring, baselines play a critical role in detecting anomalies by establishing a reference point for what is considered normal system behavior. A baseline is built from historical performance data, common metrics measured include CPU usage, memory consumption, network traffic, or application response times. By comparing current metrics against this baseline, monitoring tools can identify unusual patterns or deviations that may indicate performance issues, security threats, or system failures. Baselines also adapt over time, accounting for expected variations and trends such as peak business hours or seasonal patterns. This proactive approach enables faster incident detection, reduces false alarms, and supports more accurate root cause analysis.

AIOps-based monitoring tools leverage statistical methods and machine learning to build up dynamic baselines unique to each system. The quality of the baseline formed is inherent to the quality and effectiveness of the resultant anomaly detection.

To learn more about automated baselines, see: What is Automatic Baselining? - IT Glossary | eG Innovations.


Metric Thresholds and Anomaly Detection

Anomaly detection depends largely on detecting deviations from the expected baseline based on historical past performance. Most enterprise monitoring tools will offer some control over anomaly detection via the provision of dynamic thresholds, where some measure of what is considered a significant deviation can be made to avoid false alerts and alert storms.

The more advanced monitoring tools provide the capabilities to combine static and dynamic metric thresholds to ensure stable anomaly detection. To learn more, see Static vs Dynamic Alert Thresholds for Monitoring | eG Innovations.

Accurate anomaly detection usually relies on other mechanisms to eliminate noise and statistically insignificant events. Techniques implemented in monitoring tools include:

  • Granular alert severities – anomalies in certain metrics will have greater significance than in other metrics
  • Alarm windows and sampling – over how long a period or number of samples is an anomaly considered significant
  • Event correlation and grouping – any IT disruption will result in a large number of anomalies being detected. Grouping and correlating events is essential to avoid alert storms

AIOps and Anomaly Detection

In enterprise level IT monitoring tools, AIOps plays an important role in automating and scaling anomaly detection. Leveraging machine learning in combination with other numerical techniques, AIOps-based monitoring tools can process and identify patterns within data far beyond the capabilities of a manual operator.

Auto-discovery and auto-deploy technologies within AIOps platforms ensures that anomaly detection occurs without delay and the need for manually-instigated deployment. This is especially important within dynamic or ephemeral systems such as Kubernetes or cloud.

The number of metrics, events, logs and traces analyzed by a monitoring platform for anomalies is important for a proactive monitoring strategy. Whilst many tools will analyze headline metrics such as RAM, CPU and IOPs, it is anomalies in metrics not normally watched by a human operator that will often give the first warning signs of an IT issue long before user experience or application performance is impacted. When evaluating the quality of anomaly detection offered, coverage of metrics should be considered, and whether the monitoring tool will detect anomalies such as:

  • Handle leaks in an application
  • A gradual increase in a Java applications’ memory heap usage
  • Packet drops on a router
  • Fragmented indexes in SQL databases
  • Storage issues

Why Anomaly Detection Matters for IT Operations & Security

Choosing IT monitoring tools with good anomaly detection, helps organizations with:

  • Cybersecurity: Detecting malware, DDoS attacks, and insider threats. Anomalies such as a high number of login attempts at 3am on a Sunday often reveal malicious attacks.
  • IT Performance Monitoring: Identifying infrastructure failures, slowdowns, and outages before they impact users. Anomalies such as a server using 200% of its normal CPU usage often indicate issues long before static metric thresholds are breached.
  • Compliance & Risk Management: Meeting standards and frameworks such as NIS2, ISO 27001, and DORA. Many risk and compliance frameworks state that organizations must have proactive anomaly detection in place.

Anomaly Detection vs. Predictive Analysis

Anomaly detection and predictive analysis are both important techniques in IT operations, and monitoring, but they serve different objectives.

Anomaly detection is about identifying data points, events, or behaviors that deviate from the expected norm. It answers the question: “Is something unusual happening right now?” For example, sudden spikes in network traffic, unexpected server downtime, or a surge in login failures could be flagged as anomalies. It focuses on real-time or historical deviations that may indicate performance issues, cyberattacks, or misconfigurations.

Predictive analysis, by contrast, looks forward. It uses historical data, statistical models, and machine learning to forecast future outcomes. It answers the question: “What is likely to happen next?”, for example, predicting when disk space will run out, estimating future application load during peak hours, or forecasting system failures before they occur.

Generally, anomaly detection is reactive and diagnostic, alerting you when something unexpected occurs, while predictive analysis is proactive and forward-looking, helping prevent issues by anticipating future trends.

Under-the-hood both techniques leverage similar mathematical and / or computational techniques and algorithms to analyze data from IT systems and applications.