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1. Find the alert and confirm you have access
Open the Microsoft Defender portal and locate the alert in the Alerts queue or through its incident. The queue can be filtered by severity, status, category, detection source, alert type, product, affected entities, and automated-investigation state.
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Alert access may be available through Microsoft Entra roles such as Security Reader, Security Operator, or Security Administrator, or through qualifying custom Defender roles. Sentinel data has a separate requirement: you also need appropriate permissions for the associated workspace. Check your tenant’s role assignments if an alert or its evidence is not visible.
2. Read the alert as evidence, not the whole story
Open the alert and review its summary, source, chronology, and affected entities. The Defender queue can include signals from Defender for Endpoint, Defender for Office 365, Defender for Identity, Defender for Cloud Apps, Microsoft Entra ID Protection, Microsoft Sentinel, and Microsoft Data Loss Prevention. Available actions beside an entity vary by alert type.
Check whether the alert belongs to an incident. Microsoft describes alerts as individual signals or evidence and incidents as correlated collections that present a wider attack story. Use the alert to understand the detection; use the incident to see related alerts, assets, and chronology. For Office 365 incidents, Microsoft’s workflow describes this in its investigation and response guide.
3. Triage severity and decide what needs attention first
Assess severity and priority alongside the affected assets, related alerts, and available context. Decide whether the case needs immediate containment, escalation to another team, or continued monitoring. Severity alone does not establish the full scope or impact, so consider it with the incident’s evidence and asset list.
Some incidents may be handled by automation rules when they are created. The rules can triage, manage, or respond to incidents, but their presence does not mean every incident follows the same automated path. Confirm what actually happened in the incident and action records.
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Follow the incident’s attack story and chronology, then inspect its alerts, impacted assets, evidence, related activity, and any automated investigation results. Depending on the case, affected entities may include users, mailboxes, and endpoints. Use the incident graph to examine relationships between entities when the list view does not make the connections clear.
For an Office 365 incident, the Evidence and Response view can surface related items and pending actions. Review the underlying investigation or incident graph when you need more detail about an entity or its relationship to other activity. Microsoft’s Office 365 investigation guide documents these views.
- Identify which users, mailboxes, devices, or other assets are affected.
- Connect related alerts and activity in time order; distinguish confirmed evidence from items that still need validation.
- Review investigation findings and recommended actions before deciding how broadly to respond.
5. Contain and eradicate based on verified scope
Choose actions that match the evidence and affected assets. Microsoft’s examples include disabling compromised users, isolating affected devices, blocking malicious IP addresses, and approving remediation actions. Automated investigations may propose steps such as quarantining a file, stopping a process, isolating a device, or blocking a URL.
Before approving a proposed remediation, check the affected entity and the action’s scope. Depending on configuration, a response may run automatically or wait for approval. Use Action center to review pending actions and track completed ones; do not assume that an investigation finding has already been remediated.
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Automation can speed response, but it is conditional. Microsoft Learn states: “Not every alert triggers an automated investigation, and not every investigation results in automated remediation actions.” Review investigation results and Action center to determine whether work is pending, completed, or was not initiated. The available actions and approval requirements depend on the workload and tenant configuration.
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Once containment and eradication are complete, restore affected users, devices, workloads, or tenant resources to a trusted state. Validate that the threat is no longer active before treating recovery as complete.
Record the outcome, classification, determination, response actions, and resolution details. Complete required handoffs and tasks, then use the incident review to identify appropriate changes to workflows, playbooks, automation rules, detections, or security configuration.
Access, licensing, and workload differences
There is no single Microsoft 365 license requirement that applies to every alert investigation. Microsoft notes that some alerts can be accessed without a Defender XDR license, giving access through Defender for Office 365 as an example; settings and capabilities vary by license level. Requirements for a particular workflow or action should be checked for that workload and tenant.
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| Handling path | What to investigate | Access or prerequisite to verify |
|---|---|---|
| General Defender alerts | Alert details, incident relationships, affected entities, and available investigation or response actions. | Applicable Entra or custom Defender role; workload-specific access and license settings. Microsoft says some alerts can be accessed without a Defender XDR license. |
| Defender for Office 365 incident workflow | Incident attack story, affected users and mailboxes, Evidence and Response items, investigations, and pending actions. | Defender for Office 365 Plan 2 or higher and sufficient permissions, including Search and purge, for the documented workflow. |
| Microsoft Sentinel alert data | Alert and incident context available from the Sentinel data source. | Appropriate permissions for the associated workspace, including required Azure RBAC access. |
Microsoft’s portal and feature documentation can change, and tenant configuration affects what appears or can be done. Confirm current entitlements, role assignments, alert policies, automation rules, and approval settings in your environment.
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