Attack Surface Ranked

REVIEW · SCORED SEPTEMBER 2026 · CROWDSTRIKE EASM ADDED 13 OCTOBER 2026

Microsoft Defender EASM review: external attack surface management on Azure

Quick answer

Microsoft Defender External Attack Surface Management ranks seventh of ten at 6.00 out of 10. It has the best pricing transparency in the set, a 30-day free trial and a prebuilt inventory for many organizations. It scores lowest on exploitability validation and low on remediation, because both are left to other tools.

Scored September 2026 · CrowdStrike EASM added 13 October 2026 · Drawn from vendor product pages, docs and public pricing

What does Microsoft Defender EASM do?

Defender EASM is an Azure resource. Discovery starts from seeds (domains, IP address blocks, hosts, email contacts, ASNs and Whois organizations) and recurses through Whois, DNS, certificate and ASN relationships. Microsoft also offers a prebuilt inventory for many organizations, which it recommends as the starting point.

Assets are sorted into states: Approved Inventory, Dependency, Monitor Only, Candidate and Requires Investigation, based on connection strength and confidence scores. Dashboards cover vulnerabilities, compliance and security hygiene. Data connectors export assets and insights to Log Analytics and Azure Data Explorer, where teams can create incidents, build playbooks and trigger remediation actions. A Security Copilot integration is in preview.

One limit matters for groups: Microsoft states that Defender EASM does not support cross-tenant resource access, including through Azure Lighthouse.

What does a finding arrive with in Microsoft Defender EASM?

  • Owner or subsidiary attributedPartial
  • Exploitability provenNot documented
  • Ticket or workflow createdPartial
  • Compensating control appliedNot documented
  • Fix retestedNot documented

Microsoft owner: confidence-based asset states; ticket: via export to Log Analytics.

A Defender EASM finding arrives with a confidence-based state. Ticketing and remediation happen after export to Log Analytics. Exploit validation, compensating controls and retesting are not documented.

How does Microsoft Defender EASM score on each criterion?

DIS Discovery of unknown assets and subsidiaries

Offers a prebuilt inventory for many organizations and recursive discovery from seeds: domains, IP blocks, hosts, email contacts, ASNs and Whois organizations.

20% · 7 / 10

ATT Attribution accuracy and false-positive handling

Every asset carries a state (Approved Inventory, Dependency, Monitor Only, Candidate, Requires Investigation) based on connection strength and confidence.

15% · 7 / 10

VAL Exploitability validation

Dashboards cover vulnerabilities, compliance and security hygiene; no exploitability testing is documented.

15% · 3 / 10

REM Remediation and mitigation support

Remediation happens downstream after export to Log Analytics; no built-in remediation workflow is documented.

20% · 4 / 10

INT Integrations and platform reach

Data connectors to Log Analytics and Azure Data Explorer and a Security Copilot integration in preview; no cross-tenant resource access.

10% · 8 / 10

TTV Time to value

30-day free trial on the first resource, plus the prebuilt inventory.

10% · 8 / 10

PRC Pricing transparencyTOP

Self-serve Azure billing against a published definition of billable assets (approved hosts, domains and IP addresses) after the trial.

10% · 7 / 10

Where is Microsoft Defender EASM strongest?

  • Pricing transparency: published billable-asset definition, 30-day trial, Azure billing.
  • Fast start from a prebuilt inventory.
  • Clear confidence states for doubtful assets.

What should buyers check before choosing Microsoft Defender EASM?

  • No exploit validation.
  • Remediation depends on your own Sentinel or Log Analytics workflows.
  • No cross-tenant resource access for multi-tenant subsidiaries.

How much does Microsoft Defender EASM cost?

After a 30-day free trial on the first resource, customers are charged on their count of billable assets: approved host:IP combinations, approved domains and approved IP addresses. Assets in other states are not charged. Charges appear on the Azure bill as a separate Defender EASM line. Check Microsoft's pricing page for the current rate.

Who should shortlist Microsoft Defender EASM?

Azure-first teams that want to see their external footprint before committing budget, and teams that already run Microsoft Sentinel.

Frequently asked questions

Is there a free trial of Microsoft Defender EASM?

Yes. Microsoft grants a 30-day free trial when you create your first Defender EASM resource.

What counts as a billable asset?

Approved host:IP combinations, approved domains and approved IP addresses.

Is Microsoft Defender EASM being retired?

We found no retirement notice on Microsoft's documentation, which was last updated in May 2026.

What are the alternatives?

Sources: Overview, What is discovery, Billable assets, Data connections, Pricing · Reviewed September 2026