Manage Alert Suppression Rules
Implementation Effort: Medium
Managing alert suppression rules requires security teams to define, monitor, and periodically review suppression logic to avoid missing critical alerts while reducing noise.
User Impact: Low
All actions are performed by security administrators; no direct user involvement is required.
Overview
In Microsoft Defender for APIs, alert suppression rules help reduce alert fatigue by hiding known, non-actionable alerts from the Defender for Cloud portal. These rules are especially useful in environments where certain API behaviors are expected and do not require investigation.
Key Capabilities
- Suppress Known Benign Alerts: Suppression rules can be applied to alerts that are triggered by known tools, configurations, or expected API behaviors 1.
- Rule Management: Administrators can create, view, edit, or delete suppression rules using the Defender for Cloud portal or REST API 1.
- Scope and Conditions: Rules can be scoped to specific subscriptions, resource types, or alert types, and can include conditions such as severity or alert name 1.
- Audit and Review: Suppressed alerts are still logged and can be reviewed later for auditing or tuning purposes.
How to Manage Suppression Rules
- Go to Microsoft Defender for Cloud.
- Navigate to Environment settings > Alerts > Suppression rules.
- Create a new rule or manage existing ones by editing or deleting them.
- Use the REST API for automation or bulk rule management 1.
Best Practices
- Regularly review suppression rules to ensure they are still valid.
- Avoid suppressing high-severity alerts unless fully justified.
- Document the rationale for each rule for audit and compliance purposes.
Improper use of suppression rules can lead to missed detections and delayed responses to real threats. This capability supports the Zero Trust principle of "Assume breach" by ensuring that alert management is intentional, auditable, and risk-aware.