Building a Next-Gen Active Learning Cyber Defense System

Decision Intelligence

This post will outline my views on creating an “Active Learning Cyber Defense System.” The type of active learning defense system I am describing can make “Real-Time Security Decisions.” For clarification in this instance, “real-time” would be:

Ingest –> Analyze –> Execute = (Under 1000ms) or under 1 second from start to finish.

Let’s find out how I do this.


Consider this a 30-thousand-foot view of the individual pieces and underlying technologies I’ve used to accomplish this. In order to complete this, I’m essentially creating a comprehensive cybersecurity AI solution for log analysis, anomaly detection, contextual interpretation, and decision intelligence to take action that requires a multi-faceted approach. The solution would harness advanced AI/ML techniques and enhanced data processing capabilities.

The 2 Keys Needed to Make Real-Time Decisions


  • Reducing the time from an event occurring to decision execution.


  • Reduce the time from ingestion to query.

Here’s a general outline to accomplish this:

Primary Goal

Detect anomalies within various logs and decide on the appropriate action to take and then take said action.

Secondary Goal

Continuously learn from new data, trends, and false positives/negatives to improve detection accuracy.

Streaming Data Collection & Integration

Log Aggregation:

Implement a centralized log management solution that can handle various log sources: DNS, system, network, firewalls, routers, servers, applications, IoT devices, etc.

Data Enrichment:

Enrich log data with threat intelligence feeds, geolocation data, and other relevant data sources.


Convert logs into a consistent format, facilitating easier analysis.

Underlying Technology:

Apache Kafka

Ensures that no events are missed or dropped due to TCP Back Pressure.

  • Separate “Topics” for individual customers and/or different data source types, such as DNS, Syslog, etc.

Apache Accumulo

Used for storage of data utilizing HDFS.

Streaming Data Preprocessing

Noise Reduction:

Filter out benign, routine events that don’t represent any threat.

Feature Extraction:

Identify and extract relevant features from the logs that are crucial for anomaly detection. This could include but is not limited to:

  • From the logs, extract valuable features like the frequency of a particular event, time stamps, origin of requests, etc.

Underlying Technology:

Apache Spark

Used for processing data and some baseline machine learning models.

Contextual Anomaly Detection


Establish normal behavioral patterns for users, applications, and devices.

  • Use historical data to calculate baseline statistics for typical behavior for different metrics.

Advanced Machine Learning Models:

Statistical Methods

For metrics with predictable patterns, use statistical thresholds (like 3σ) to detect anomalies.

Machine Learning Models

Implement unsupervised learning models such as clustering (like DBSCAN) or Autoencoders, Isolation Forest, and One-Class SVM for identifying events that deviate from the norm.

Temporal Analysis:

Identify trends and patterns over time to catch slow-burning threats or attacks that play out over extended periods.

Underlying Technology:

Apache Lucene

Provides our real-time search.

Contextual Analysis

For every detected anomaly, gather contextual data to help in decision-making. This can involve the following.

Threat Intelligence Integration:

  • Match events against known threat indicators or adversaries’ tactics, techniques, and procedures (TTPs).
  • Tracking the origin and understanding if it comes from a previously flagged IP.
  • Checking if the anomaly coincides with any known vulnerability patches or system changes.

User and Entity Behavior Analytics (UEBA):

Gain insights into the typical behavior of users and entities and flag deviations.


  • Correlating the event with other events around the same time.
  • Relate disparate events to recognize multi-stage attacks.

Intelligent Decision Making & Action

Scoring System:

Assign risk scores to events based on severity, impact, and likelihood.

Rules and Heuristic Engines:

Have predefined rules for certain types of anomalies (e.g., if an anomaly originates from a blacklisted IP, block immediately).

Decision Trees:

Utilize decision trees or other decision-making algorithms to decide the most appropriate action (e.g., alert, block, ignore). Given the features and context of an anomaly, predict the most likely necessary action.

Feedback Loop:

Constantly incorporate feedback on the decisions. If a certain action resulted in a false positive, feed that information back into the system. Incorporate feedback from security analysts to refine the decision-making process continually.

Response & Automation


Notify security teams of high-risk events.

Orchestration and Automation:

Integrate with Security Orchestration, Automation, and Response (SOAR) platforms to take automatic actions like blocking IPs, disabling accounts, or isolating devices.

Incident Response Integration:

Automate the creation of incident response tickets and provide analysts with all the context they need to investigate further.

Continuous Learning & Improvement


Continually train the AI models with new data, especially as the company’s environment evolves.

Transfer Learning:

Incorporate knowledge from global threat intelligence databases or external sources to stay updated with the latest threat vectors.

Tuning & Optimization:

Regularly review and refine the AI’s parameters, thresholds, and decision-making criteria to ensure optimal performance.

Monitoring & Reporting


Regularly evaluate the system’s performance using metrics like a Confusion Matrix to determine the system’s detection performance. Adjust the system based on these evaluations. For instance, if the false positive rate is high, adjusting thresholds or retraining models may be worthwhile.


Create intuitive dashboards that display key metrics, high-risk events, and the AI’s decision-making rationale.

Forensic Capabilities:

Allow security analysts to dive deep into events, pulling up raw logs, related events, and historical data.

Regulatory Compliance:

Ensure the AI solution adheres to relevant regulatory requirements and can produce reports as needed for compliance checks.

Scalability & Evolution

Cloud-Native Design:

Design the system to be scalable, taking advantage of cloud-native architectures and elastic resources.

Incorporate New Technologies:

Continually assess and integrate emerging AI/ML techniques and cybersecurity technologies.

Open API Integration:

Ensure the solution can integrate with new tools, platforms, or data sources via open APIs.

Ethics & Privacy

Data Privacy:

Implement strict data privacy controls and ensure adherence to data protection regulations.

Bias Minimization:

Regularly test and refine the AI models to minimize any unintended biases in decision-making.


Implementing such an advanced cybersecurity AI solution would require collaboration between AI specialists, cybersecurity experts, and infrastructure architects. Regular testing, iteration, and feedback are crucial to ensure the system remains effective against evolving threats.

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