HEAD-TO-HEAD · FACTS ONLY
Defender EASM vs Tenable ASM: exposure management facts side by side
SHORT ANSWER
Defender EASM describes 2 of the five tool types on the pages we read and Tenable ASM describes 4; they differ on exposure validation and exposure management platforms. On proof, Defender EASM does not describe exploit testing on the pages we read and Tenable ASM describes exploitability checks but not attack-style testing. We do not score either; the right choice depends on your estate, current platform, WAFs and capacity to fix.
By The Exposure Desk · Exposure Management Finder · Published 2026-10-11
Desk research from public vendor pages read in September 2026, updated 2026-10-11. Profiles follow our published method; we did not run the products.
How do their shapes compare?
- Microsoft Defender EASM
- Tenable Attack Surface Management
- Outer point: described on the vendor's pages we read
- Inner point: not in our sources (it may exist; we did not find it)
What are the facts, side by side?
| Fact | Microsoft Defender EASM | Tenable Attack Surface Management |
|---|---|---|
| Positioning | Microsoft's external attack surface management service, run as an Azure resource, with a prebuilt inventory, recursive discovery from seeds and billing on the Azure bill. | Tenable's attack surface management, part of the Tenable One exposure management platform, drawing on an attack surface map of more than 5 billion assets. |
| Deployment | An Azure resource. Cross-tenant resource access, including Azure Lighthouse, is not supported. Source: Microsoft Learn: Defender EASM overview · Read 27 Sep 2026 | Part of Tenable One; sold through a demo request. Source: Tenable Attack Surface Management · Read 27 Sep 2026 |
| EASM discovery | Described A prebuilt inventory for many organisations plus recursive discovery from seeds you supply. Source: Microsoft Learn: what is discovery · Read 27 Sep 2026 | Described Identifies domains related to your inventory from a map of 5 billion+ assets, with 200+ metadata fields. Source: Tenable Attack Surface Management · Read 27 Sep 2026 |
| Exposure validationDiffers | Not in our sources | Described Tenable One adds attack path analysis across 150+ techniques; exploit testing is not described for the ASM product. Source: Tenable One · Read 27 Sep 2026 |
| Exposure management platformsDiffers | Not in our sources | Described Feeds Tenable One, which Tenable calls its exposure management platform, with Tenable One Connectors for third-party data. Source: Tenable One · Read 27 Sep 2026 |
| CTEM programme support | Described Covers discovery and inventory with dashboards for vulnerabilities, compliance and hygiene; remediation happens downstream through Log Analytics and Azure Data Explorer. Source: Microsoft Learn: data connections · Read 27 Sep 2026 | Described Tenable One covers discovery, attack paths and Hexa AI automated remediation workflows; exploit validation is not described. Source: Tenable One · Read 27 Sep 2026 |
| WAF posture | Not in our sources | Not in our sources |
| Subsidiary and owner attributionDiffers | Partly Every asset carries a state (Approved Inventory, Dependency, Monitor Only, Candidate, Requires Investigation) based on connection strength and confidence; cross-tenant access is not supported. Source: Microsoft Learn: what is discovery · Read 27 Sep 2026 | Not in our sources |
| Internal as well as external assetsDiffers | Not in our sources | Matches Tenable One includes vulnerability management alongside external attack surface data. Source: Tenable: buy · Read 27 Sep 2026 |
| Cloud connections namedDiffers | Partly Runs as an Azure resource; connections to other clouds are not described. Source: Microsoft Learn: data connections · Read 27 Sep 2026 | Not in our sources |
| Exploitability checkedDiffers | Not in our sources | Partly Attack path analysis across 150+ techniques in Tenable One, not exploit testing. Source: Tenable One · Read 27 Sep 2026 |
| Attack-style testing | Not in our sources | Not in our sources |
| Works through your WAF or edge | Not in our sources | Not in our sources |
| WAF coverage across several vendors | Not in our sources | Not in our sources |
| Retests after a fix | Not in our sources | Not in our sources |
| Routes findings to owners and tickets | Partly Data connectors to Log Analytics and Azure Data Explorer trigger remediation actions downstream. Source: Microsoft Learn: data connections · Read 27 Sep 2026 | Partly Tenable One Advanced lists orchestrated remediation through manual or automated ticketing workflows. Source: Tenable One pricing · Read 11 Oct 2026 |
| Applies a compensating controlDiffers | Not in our sources | Partly Hexa AI orchestrates automated remediation in Tenable One. Source: Tenable One · Read 27 Sep 2026 |
| Price or pricing basis publishedDiffers | Partly Billable assets are defined (approved host:IP combinations, domains and IP addresses) and charged on the Azure bill; Microsoft's pricing page showed no rate when we read it. Source: Microsoft Learn: understanding billable assets · Read 27 Sep 2026 | Not in our sources |
| Trial or self-serve startDiffers | Matches A 30-day free trial, then Azure billing. Source: Microsoft Learn: understanding billable assets · Read 27 Sep 2026 | Not in our sources |
| Platform it extends | Native to Azure, billed on the Azure bill, with a Security Copilot integration in preview. Source: Microsoft Learn: Defender EASM documentation · Read 27 Sep 2026 | External findings feed Tenable One next to Tenable vulnerability data. Source: Tenable One · Read 27 Sep 2026 |
| Integrations | Data connections to Log Analytics and Azure Data Explorer, and a Security Copilot integration in preview. Source: Microsoft Learn: data connections · Read 27 Sep 2026 | Tenable One Connectors bring third-party data into the platform. Source: Tenable One · Read 27 Sep 2026 |
| Price | Billed through Azure on billable assets (approved host:IP combinations, domains and IP addresses) after a 30-day free trial. Microsoft's pricing page did not show a rate when we read it; check it for the current figure. Source: Microsoft Learn: understanding billable assets · Read 27 Sep 2026 | Not published. Tenable One is sold in two packages, Foundation and Advanced, both by quote; ASM is not sold online. Tenable publishes some adjacent prices, for example Tenable One Vulnerability Management at $3,700 for one year for up to 250 assets. Source: Tenable One pricing · Read 11 Oct 2026 |
Where do they differ?
- Exposure validation: Defender EASM is not in our sources; Tenable ASM describes it.
- Exposure management platforms: Defender EASM is not in our sources; Tenable ASM describes it.
- Subsidiary and owner attribution: Defender EASM partly matches; Tenable ASM is not in our sources.
- Internal as well as external assets: Defender EASM is not in our sources; Tenable ASM matches.
- Cloud connections named: Defender EASM partly matches; Tenable ASM is not in our sources.
- Exploitability checked: Defender EASM is not in our sources; Tenable ASM partly matches.
- Applies a compensating control: Defender EASM is not in our sources; Tenable ASM partly matches.
- Price or pricing basis published: Defender EASM partly matches; Tenable ASM is not in our sources.
- Trial or self-serve start: Defender EASM matches; Tenable ASM is not in our sources.
Choose Defender EASM if
- You are on Azure and want to start without a sales call
- You want a discovery baseline before buying validation
Choose Tenable ASM if
- You already run Tenable vulnerability management
- You want external findings in the same platform as internal vulnerabilities
Which limits should you check?
Defender EASM
- No exploit validation is described.
- No built-in remediation workflow, and no cross-tenant resource access for groups with several Azure tenants.
Tenable ASM
- ASM is quote-only, with no trial listed.
- Exploit testing is not described, and remediation depends on buying into Tenable One.
Questions readers ask
Is Defender EASM or Tenable ASM better?
Neither is scored on this site. Defender EASM describes 2 of five tool types and Tenable ASM 4 on the pages we read, and they differ on 9 recorded facts. Which fits depends on your estate, current platform, need for proof, WAFs and capacity to fix; the finder checks those.
Which of the two proves exploitability?
Defender EASM: exploitability checked: Not in our sources; attack-style testing: Not in our sources. Tenable ASM: exploitability checked: Partly; attack-style testing: Not in our sources.
Do Defender EASM or Tenable ASM publish prices?
Defender EASM: Billed through Azure on billable assets (approved host:IP combinations, domains and IP addresses) after a 30-day free trial. Microsoft's pricing page did not show a rate when we read it; check it for the current figure. Tenable ASM: Not published. Tenable One is sold in two packages, Foundation and Advanced, both by quote; ASM is not sold online. Tenable publishes some adjacent prices, for example Tenable One Vulnerability Management at $3,700 for one year for up to 250 assets.