7 Best Attack Surface Management Tools in 2026

Attack surface management (ASM) tools provide continuous visibility into an organization's external-facing assets -- domains, subdomains, IP addresses, cloud instances, APIs, and any other internet-accessible infrastructure. The ASM market reached $1.5B in 2025 and is projected to grow to $5-12B by 2030, reflecting the reality that organizations have lost track of their own digital footprint. Cloud sprawl, shadow IT, M&A integration, and developer self-service have made it impossible to maintain asset inventories manually.

The Verizon 2025 DBIR found that vulnerability exploitation accounts for 20% of initial access in breaches. Many of those exploited vulnerabilities exist on assets the organization did not know about -- forgotten staging servers, legacy applications, acquired company infrastructure that was never consolidated. ASM solves this visibility gap.

What to Look for in an ASM Tool

Not all ASM tools are equivalent. Evaluate along these dimensions:

• Asset discovery: How does it find assets? DNS enumeration, CT logs, passive DNS, cloud API integration, web crawling?
• Continuous monitoring: How frequently does it scan? Daily? Hourly? Real-time?
• Risk prioritization: Does it just list assets, or does it score risk and prioritize findings?
• Reporting: Can you share findings with non-technical stakeholders?
• Integration: Does it connect with your SIEM, ticketing system, and cloud providers?
• Pricing model: Per asset? Per domain? Flat rate? Enterprise-only?

1. MAGO Intelligence

Best for: On-demand domain intelligence and vendor assessment
Pricing: Free tier + per-scan + subscription
Website: mago.team

MAGO provides on-demand attack surface intelligence for specific targets. Enter a domain or IP, and it runs 16 intelligence modules in parallel: subdomain enumeration, DNS analysis, security header auditing, WHOIS profiling, technology fingerprinting, TLS assessment, and threat intelligence correlation from AlienVault OTX, ThreatFox, URLhaus, and AbuseIPDB.

MAGO differentiates through output quality. Results are structured reports readable by non-technical stakeholders -- not raw data dumps requiring engineering time to interpret. This makes it particularly valuable for vendor risk assessment, legal due diligence, and ad hoc security investigations where the audience includes people outside the security team.

2. Censys ASM

Best for: Enterprise continuous attack surface monitoring
Pricing: Enterprise (contact sales)
Website: censys.io

Censys ASM provides continuous discovery and monitoring of internet-facing assets. Built on the Censys internet-wide scanning platform (powered by ZMap), it automatically discovers assets belonging to your organization, monitors them for changes, and flags exposures. Censys has particularly strong TLS certificate intelligence, enabling discovery of assets through certificate relationships.

The enterprise positioning means Censys ASM is designed for large organizations with complex, multi-domain environments. Pricing requires a sales engagement, which limits accessibility for smaller teams. For a detailed comparison, see Shodan vs Censys vs MAGO.

3. Microsoft Defender EASM

Best for: Organizations already in the Microsoft security ecosystem
Pricing: Per-asset/day pricing, integrated with Azure

Microsoft Defender External Attack Surface Management (EASM) continuously discovers and maps internet-facing resources associated with your organization. It benefits from Microsoft's massive internet scanning infrastructure and integrates natively with Microsoft Sentinel, Defender for Cloud, and the broader Microsoft 365 Defender ecosystem.

If your security operations already run on Microsoft, EASM is a natural extension. If you are a multi-vendor shop, the Microsoft-centric integration may be less valuable. Pricing is consumption-based (per asset per day), which scales linearly -- a consideration for organizations with large asset inventories.

4. Mandiant Attack Surface Management

Best for: Threat-intelligence-enriched ASM
Pricing: Enterprise (contact sales)

Mandiant (now part of Google Cloud) combines asset discovery with Mandiant's extensive threat intelligence library. The platform discovers external assets, enriches findings with known threat actor targeting data, and prioritizes based on real-world exploitation intelligence. This threat-led approach helps security teams focus on the vulnerabilities adversaries are actually exploiting, not just theoretical risk scores.

5. Palo Alto Cortex Xpanse

Best for: Large enterprise continuous monitoring at scale
Pricing: Enterprise (contact sales)

Cortex Xpanse (formerly Expanse) operates its own internet-wide scanning infrastructure, providing independent discovery without relying on third-party data sources. It scans the entire IPv4 space multiple times per day, enabling near-real-time detection of new exposures. Xpanse integrates with the broader Cortex platform for automated remediation workflows.

Xpanse is positioned for large enterprises and government organizations. The independent scanning capability provides the most comprehensive and current view of an organization's external footprint, but the enterprise pricing and implementation complexity may be disproportionate for smaller organizations.

6. ProjectDiscovery Cloud Platform

Best for: Technical teams wanting open-source-based ASM
Pricing: Free tier + paid cloud platform
Website: projectdiscovery.io

ProjectDiscovery builds on its popular open-source tools (subfinder, httpx, nuclei, katana) to provide a cloud-based ASM platform. Assets discovered through the open-source toolchain are monitored continuously, and Nuclei templates enable automated vulnerability detection. The platform bridges the gap between ad hoc tool usage and continuous monitoring.

The open-source foundation means technical teams can customize and extend the platform. The tradeoff: it requires more security engineering expertise to operate effectively compared to fully managed enterprise solutions.

7. CrowdStrike Falcon Surface

Best for: Organizations using CrowdStrike for endpoint protection
Pricing: Enterprise (part of Falcon platform)

CrowdStrike Falcon Surface (formerly Reposify) provides external attack surface monitoring integrated with the Falcon platform. The key advantage is correlation: external exposure data from Falcon Surface combined with endpoint telemetry from Falcon creates a unified view of both external and internal security posture. A vulnerable external service detected by Falcon Surface can be correlated with the host's endpoint protection status in Falcon.

Comparison Matrix

Choosing the Right ASM Tool

For ad hoc investigations and vendor assessment: MAGO provides instant intelligence reports without platform commitment or enterprise sales cycles. Ideal for teams that need answers now.

For enterprise continuous monitoring: Censys ASM, Cortex Xpanse, or Falcon Surface provide the continuous scanning and platform integration that large security operations require. Choose based on your existing security stack.

For technical teams on a budget: ProjectDiscovery's cloud platform built on open-source tools provides capable ASM with a free tier and transparent pricing.

For Microsoft shops: Defender EASM's native integration with Sentinel and the Defender ecosystem makes it the lowest-friction option if you are already invested in Microsoft security.

The IBM Cost of a Data Breach 2025 report found that organizations with mature attack surface management reduced breach costs by $1.9M on average. The attack surface management guide covers the strategic framework; the tools in this list provide the execution.