Attack Surface Management -- Tenable Alternatives
Attack surface management (ASM) provides continuous discovery and assessment of an organization's external and internal attack surface, identifying internet-facing assets, shadow IT, exposed services, and potential entry points that attackers could exploit. Unlike traditional vulnerability scanning that assesses known assets, ASM starts from the attacker's perspective to discover unknown assets, abandoned infrastructure, and misconfigured services across the entire digital footprint. These Tenable alternatives offer different approaches to attack surface discovery and assessment.
Identify all internet-facing assets associated with your organization including domains, subdomains, IP addresses, web applications, API endpoints, and cloud services. Use external scanning to discover assets from the attacker's perspective, including shadow IT, forgotten infrastructure, and third-party hosted services that may not appear in internal asset inventories.
Complement external discovery with comprehensive internal asset scanning to identify all devices, servers, workstations, network equipment, and IoT/OT devices on internal networks. Use a combination of active scanning, agent deployment, network traffic analysis, and DHCP/DNS log correlation to build the most complete internal asset inventory possible.
Evaluate discovered assets for exploitable vulnerabilities, misconfigurations, exposed sensitive services, weak authentication, default credentials, and unnecessary attack surface. Prioritize findings based on internet accessibility, vulnerability severity, exploit availability, and asset business criticality. Internet-facing assets with known exploited vulnerabilities should be the highest priority.
Remediate high-risk exposures by decommissioning unnecessary internet-facing services, patching exploitable vulnerabilities, hardening configurations, implementing network segmentation, and enforcing strong authentication. Remove shadow IT and abandoned infrastructure that no longer serves a business purpose. Reduce the attack surface proactively rather than only patching known vulnerabilities.
Establish continuous monitoring for attack surface changes including new internet-facing assets, configuration drift, certificate expirations, newly published CVEs affecting your stack, and unauthorized services. Alert on significant attack surface changes and integrate ASM findings with your vulnerability management and security operations workflows.
Custom pricing based on asset count / Typically from $3,000/year for small environments
The most comprehensive ASM alternative with external attack surface scanning, internal vulnerability assessment, and cloud asset discovery combined in a single platform. Qualys EASM (External Attack Surface Management) module extends VMDR with internet-facing asset discovery.
Free (open source) / ProjectDiscovery Cloud Platform from $100/month
The best open-source tool for attack surface assessment with fast, template-based scanning that covers exposed panels, default credentials, technology detection, and misconfiguration discovery. Combined with ProjectDiscovery's subfinder and httpx tools, Nuclei provides a complete open-source ASM workflow.
Add-on to CrowdStrike Falcon platform / Custom pricing
Provides real-time endpoint attack surface visibility through the Falcon platform, identifying vulnerable software and exploitable configurations on managed endpoints. CrowdStrike Falcon Surface extends to external attack surface discovery.
Custom pricing based on environment size / Typically $3-5/asset/month
Managed attack surface assessment as part of the broader Arctic Wolf security operations service. Dedicated security engineers discover and assess the external attack surface, providing prioritized findings with remediation guidance.
Included with Microsoft Defender for Endpoint P2 / Standalone add-on $3/user/month
Provides endpoint attack surface assessment including browser extension inventory, certificate monitoring, and security baseline assessment. Microsoft Defender EASM extends to external attack surface discovery for Microsoft licensing customers.
Cloud-native vulnerability management platform with integrated detection, prioritization, and patch management
Custom pricing based on asset count / Typically from $3,000/year for small environments
Organizations wanting an all-in-one cloud-based VM platform with integrated patching and asset inventory
Fast, template-based open-source vulnerability scanner with 8,000+ community-contributed detection templates
Free (open source) / ProjectDiscovery Cloud Platform from $100/month
Security teams and researchers wanting a fast, customizable, template-driven vulnerability scanner for web and infrastructure testing
EDR-integrated scanless vulnerability assessment built on the CrowdStrike Falcon platform
Add-on to CrowdStrike Falcon platform / Custom pricing
CrowdStrike Falcon customers wanting vulnerability visibility without deploying additional scanning infrastructure
Managed security operations platform with concierge-delivered vulnerability management services
Custom pricing based on environment size / Typically $3-5/asset/month
Organizations without in-house security expertise wanting fully managed vulnerability scanning and prioritized remediation guidance
Microsoft's built-in vulnerability management integrated with Defender for Endpoint
Included with Microsoft Defender for Endpoint P2 / Standalone add-on $3/user/month
Microsoft-centric organizations wanting vulnerability management bundled with their existing Defender for Endpoint deployment
Vulnerability management focuses on scanning known assets for known CVEs and misconfigurations. Attack surface management starts from the attacker's perspective, first discovering what assets exist (including unknown and shadow IT) before assessing them for vulnerabilities. ASM is broader in scope — it includes asset discovery, exposure assessment, and risk prioritization across the entire digital footprint. Traditional VM assumes you know what to scan; ASM discovers what needs scanning.
Yes. Tenable offers ASM through Tenable Attack Surface Management (formerly Tenable.asm), which provides external attack surface discovery, and Tenable One, which unifies exposure management across internal and external assets. Tenable's ASM capabilities include internet-facing asset discovery, domain and subdomain enumeration, web application fingerprinting, and integration with Tenable.io vulnerability data. However, dedicated ASM platforms may provide deeper external discovery capabilities.
Yes. ProjectDiscovery's open-source toolkit (subfinder for subdomain discovery, httpx for HTTP probing, nuclei for vulnerability scanning, and naabu for port scanning) provides a capable open-source ASM workflow. These tools are widely used by security researchers and bug bounty hunters. However, they require significant security expertise to operate, lack management dashboards and reporting, and do not provide the continuous monitoring and alerting that commercial ASM platforms offer.
External attack surface scanning should run continuously or at minimum daily. Internet-facing assets are constantly being targeted by automated scanners and attackers. New assets can appear through cloud provisioning, shadow IT, or third-party services at any time. Most commercial ASM platforms provide continuous monitoring with alerting on new discoveries. Open-source workflows should be scheduled to run at least daily with results reviewed by security engineers.
Cloud-native vulnerability management platform with integrated detection, prioritization, and patch management
ComparisonFast, template-based open-source vulnerability scanner with 8,000+ community-contributed detection templates
ComparisonEDR-integrated scanless vulnerability assessment built on the CrowdStrike Falcon platform
CategoryCompare the best open source vulnerability scanner alternatives to Tenable in 2026. Greenbone OpenVAS, Nuclei — features, scanning depth, and deployment compared.
CategoryCompare the best cloud vulnerability management alternatives to Tenable in 2026. Qualys VMDR, Rapid7 InsightVM, CrowdStrike Falcon Spotlight — features, pricing, and capabilities compared.
Use CaseCompare the best Tenable alternatives for continuous vulnerability scanning in 2026. Qualys VMDR, Rapid7 InsightVM, CrowdStrike Falcon Spotlight, Nuclei — scanning capabilities compared.
Use CaseCompare the best Tenable alternatives for compliance scanning in 2026. Qualys VMDR, Rapid7 InsightVM, Greenbone OpenVAS, Tanium — CIS, DISA STIG, and PCI compliance capabilities compared.
Use CaseCompare the best Tenable alternatives for cloud vulnerability management in 2026. Qualys VMDR, Rapid7 InsightVM, CrowdStrike Falcon Spotlight, Nuclei — cloud scanning capabilities compared.