Developing Rules for Common Threat Alerting (Activity 7.2.1)

We’ve mastered log collection and standardization (Activity 7.1.2) and begun extracting deep insights from that data to understand user and device behavior (Activity 7.1.3). Now, we take the crucial step of translating that intelligence into actionable alerts, ensuring our security teams are notified precisely when and where it matters. This brings us to Zero Trust Activity 7.2.1: Threat Alerting Pt1.

This activity focuses on operationalizing threat detection within your existing Security Information and Event Management (SIEM) solution. It mandates that DoD Components utilize their existing SIEM solution to develop rules and alerts for common threat events like malware infections, phishing attempts, brute-force attacks, or common policy violations. Crucially, these alerts and/or rule triggers are fed into a parallel “Asset ID & Alert Correlation” activity (7.2.4), signifying the immediate intent to automate responses based on identified assets.

The outcomes for Activity 7.2.1 Part 1 highlight the establishment of these core alerting capabilities:

1. Rules developed for Component-derived threat correlation.
2. Rules developed for asset ID-based responses.

The ultimate end state underscores the continuous improvement driven by this activity: Components augment SIEM with threat data developed from incident response analysis. This means refining your detection capabilities based on real-world incidents.

Solutions for Achieving Threat Alerting Pt1

Implementing Activity 7.2.1 requires a systematic approach to SIEM rule development, leveraging integrated security data, and ensuring seamless hand-off to automation processes:

1. Developing SIEM Rules for Common Threat Events:
   1. Process: Components define clear, specific “common threat events” based on their threat models, historical incidents, and industry best practices (e.g., MITRE ATT&CK techniques, common malware families).
   2. Rule Creation: Translate these defined threat events into correlation rules and alerts within the SIEM solution. These rules will look for specific patterns or sequences of events within the ingested log data (from Activity 7.1.2) to trigger an alert.
   3. Prioritization: Focus initially on the most prevalent and impactful common threats that can be reliably detected with existing data sources.
2. Leveraging Integrated Security Data:
   1. The effectiveness of SIEM rules depends heavily on the quality and completeness of the ingested data. Ensure your SIEM is receiving high-quality, standardized logs from critical sources (as per Activity 7.1.2) like:
      1. Endpoint Detection & Response (EDR) platforms: For detailed endpoint telemetry.
      2. Firewalls: For network connection attempts and blocks.
      3. Identity Providers: For authentication and access logs.
      4. Threat Intelligence Platforms (TIPs): To enrich events with known malicious indicators.
3. Feeding Alerts for Asset ID & Alert Correlation:
   1. Establish mechanisms to automatically feed the generated alerts and rule triggers from the SIEM into the parallel “Asset ID & Alert Correlation” activity. This process will typically:
      1. Identify the specific asset(s) (device ID, user ID, application ID) associated with the alert.
      2. Correlate the alert with other relevant security events or asset context.
      3. Prepare the enriched alert for automated response workflows (e.g., by a SOAR platform).
4. Augmenting SIEM with Incident Response Analysis Data:
   1. Implement a feedback loop where insights and new threat data derived from actual incident response analysis (e.g., new indicators of compromise, attacker techniques) are used to continuously refine and augment existing SIEM rules and develop new ones. This ensures your detections evolve with the threat landscape.

How Trellix and Elastic Work Together to Achieve Desired Outcomes:

Your strategic choices of Trellix for endpoint security and Elastic for central SIEM/XDR are fundamental to achieving the goals of Activity 7.2.1:

• Trellix (Source of Endpoint Threat Events and Data): Trellix’s XDR platform (Endpoint Security, EDR, DLP) is a primary generator of “common threat events” at the endpoint level.
  • Direct Threat Detection: Trellix natively detects malware, exploits, and anomalous endpoint activities. These detections themselves are alerts and provide rich telemetry.
  • Feeding the SIEM: This raw telemetry and its high-fidelity alerts are fed directly into Elastic Security, providing the crucial endpoint data that Elastic needs to develop its correlation rules.
  • Context for Rules: Trellix’s insights into endpoint processes, network connections, and file activity are vital for designing effective SIEM rules that accurately identify common threats.
• Elastic Security (The SIEM/XDR and Rule Engine): Elastic Security, as your SIEM/XDR platform, is the central hub where threat alerting is operationalized.
  • Rule Development Platform: It provides the environment for security analysts to develop, test, and deploy rules based on the combined data from all sources, including Trellix. These rules identify “Component-derived threat correlation.”
  • Alert Generation: When a rule’s conditions are met (e.g., a Trellix alert correlated with an unusual login attempt from Okta data), Elastic generates the high-fidelity alert.
  • Feeding Automation: Elastic is configured to forward these alerts and relevant asset IDs to the “Asset ID & Alert Correlation” activity (likely handled by a SOAR platform like Tines). This ensures “Rules developed for asset ID-based responses.”
  • Augmenting from IR: Elastic’s powerful analytics capabilities allow it to ingest threat data generated during IR, which can then be used to augment its existing detection rules and baselines, fulfilling the activity’s end state.
• The Combined Synergy: Trellix provides the critical endpoint events and telemetry from the frontline. Elastic Security ingests this data (alongside logs from other sources like Zscaler, Okta, and Cribl), processes it, and serves as the intelligent engine that defines and triggers alerts for common threat events. This seamless flow of information ensures that your organization can rapidly identify and initiate responses to prevalent threats, moving towards a more proactive security posture.

Key Items to Consider:

• Accuracy over Quantity: Focus on developing high-fidelity rules that minimize false positives. Too many noisy alerts lead to alert fatigue and missed real threats.
• Data Quality: The effectiveness of SIEM rules is directly dependent on the quality, consistency, and completeness of the log data ingested (as emphasized in Activity 7.1.2).
• Defining “Common Threats”: Clearly define the scope of “common threat events” based on your organization’s specific threat landscape and risk profile.
• Integration with Automation: Plan how alerts will be handed off to the “Asset ID & Alert Correlation” process (likely your SOAR platform) for automated response.
• Continuous Improvement: Regularly review and refine SIEM rules based on new threat intelligence, changes in your environment, and post-incident analysis.
• Resource Allocation: Allocate sufficient resources (analysts, content developers) for continuous SIEM rule development and tuning.

For the Technical Buyer

Activity 7.2.1 is your directive to activate the early warning system of your Zero Trust architecture. It’s about transforming raw security data into actionable alerts for common threat events within your SIEM. For technical buyers, success here means leveraging your SIEM platform, like Elastic Security, to develop precise correlation rules, fueled by the rich endpoint telemetry from your EDR (e.g. Trellix). This ensures that alerts are high-fidelity and directly contribute to the “Asset ID & Alert Correlation” process, initiating your automated defenses. This activity is crucial for optimizing your detection capabilities and rapidly escalating common threats, enabling faster incident response and a more proactive security posture within your Zero Trust framework.

Pillar: Visibility & Analytics 

Capability: 7.2  Security Information and Event Management (SIEM)

Activity: 7.2.1 Threat Alerting Pt1

Phase: Target Level 

Predecessor(s): None

Successor(s): 7.2.2 Threat Alerting Pt2, 2.7.2 Implement Extended Detection & Response (XDR) Tools and Integrate with C2C Pt1