The Elastic Common Schema (ECS)

The Elastic Common Schema (ECS): Advantages in KQL Searches and Beyond

The Elastic Common Schema (ECS) is a standardized and extensible framework for structuring event and log data within the Elastic Stack. By enforcing consistent field formats across diverse data sources, ECS simplifies data analysis, improves search efficiency, and enhances the overall effectiveness of security operations. Below are the key advantages of using ECS fields in Kibana Query Language (KQL) searches and other Elastic Stack functionalities.

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1. Unified Data View

• What It Offers:

  • ECS enforces a structured and consistent approach to data representation, enabling unified views across multiple data sources.

  • Fields like event.code, source.ip, and user.name are standardized, regardless of whether the data originates from Windows logs, network traffic, endpoint events, or cloud-based systems.

• Why It Matters:

  • Analysts can seamlessly query and correlate data from different sources without needing to account for variations in field names or formats.

  • Example: A single query can analyze logs from firewalls, IDS/IPS, and endpoints using the same field names (source.ip, destination.ip).

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2. Improved Search Efficiency

• What It Offers:

  • ECS standardizes field names across all data types, simplifying the process of writing KQL queries.

  • Analysts no longer need to memorize or look up unique field names for each data source.

• Why It Matters:

  • Reduces the learning curve for new analysts and minimizes errors in query construction.

  • Example:

    event.code:4625 AND user.name:admin*

    • This query works consistently across all data sources that adhere to ECS, making it easier to identify failed login attempts targeting administrator accounts.

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3. Enhanced Correlation

• What It Offers:

  • ECS enables easier correlation of events across different data sources, which is critical for cybersecurity investigations.

  • Standardized fields like source.ip, destination.ip, and event.action allow analysts to connect related events.

• Why It Matters:

  • Provides a more comprehensive understanding of security incidents by linking disparate pieces of information.

  • Example:

    • Correlate an IP address involved in a brute-force attack with firewall logs, network traffic logs, and endpoint data to trace the attacker's activity.

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4. Better Visualizations

• What It Offers:

  • Consistent field naming conventions improve the effectiveness of visualizations in Kibana.

  • Dashboards and charts can be created more easily because all data sources adhere to the same schema.

• Why It Matters:

  • Simplifies the creation of meaningful dashboards for monitoring trends, identifying anomalies, and visualizing security incidents.

  • Example:

    • A Kibana dashboard can display failed login attempts (event.code:4625) across all endpoints, grouped by source.ip and user.name.

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5. Interoperability with Elastic Solutions

• What It Offers:

  • ECS ensures full compatibility with advanced Elastic Stack features and solutions, such as:

    • Elastic Security: For threat detection and response.

    • Elastic Observability: For monitoring system performance and application health.

    • Elastic Machine Learning: For anomaly detection and predictive analytics.

• Why It Matters:

  • Enables seamless integration with Elastic's ecosystem, unlocking advanced capabilities like automated threat hunting and anomaly detection.

  • Example:

    • Use ECS-compliant fields to train machine learning models that detect unusual login patterns indicative of credential misuse.

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6. Future-Proofing

• What It Offers:

  • ECS is the foundational schema across the Elastic Stack, ensuring compatibility with future enhancements and features.

  • As Elastic introduces new tools and capabilities, ECS-compliant data will remain compatible without requiring significant changes.

• Why It Matters:

  • Protects your investment in the Elastic Stack by ensuring long-term usability and scalability.

  • Example:

    • Future updates to Elastic Security may introduce new detection rules or visualizations that rely on ECS fields, ensuring your organization benefits immediately.

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Key ECS Fields for Security Operations

Here are some commonly used ECS fields in security-related KQL queries:

• Event Fields:

  • event.code: Identifies specific event types (e.g., 4625 for failed login attempts).

  • event.action: Describes the action taken (e.g., "login", "logout").

  • event.created: Timestamp when the event was created.

• User Fields:

  • user.name: The username associated with the event.

  • user.id: The unique identifier for the user.

• Network Fields:

  • source.ip: The source IP address of the event.

  • destination.ip: The destination IP address of the event.

• Timestamp Fields:

  • @timestamp: The time extracted from the original event.

• Winlogbeat Fields:

  • winlog.event_data.SubStatus: Sub-status codes in Windows event logs (e.g., 0xC0000072 for disabled accounts).

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Conclusion

The Elastic Common Schema (ECS) is a cornerstone of the Elastic Stack, providing a standardized and extensible framework for structuring event and log data. By adopting ECS fields, organizations can achieve:

• Unified data views across diverse sources.

• Improved search efficiency through consistent field names.

• Enhanced correlation for comprehensive incident analysis.

• Better visualizations for actionable insights.

• Interoperability with advanced Elastic solutions.

• Future-proofing for long-term compatibility.