Top 8 Attack Surface Management Tools
Choosing an attack surface management tool means deciding where on the spectrum between open-source flexibility and managed convenience you want to operate. Some platforms bundle dozens of open-source scanners into an automated pipeline. Others provide proprietary internet-wide scanning data that no single organization could collect on its own. Enterprise solutions add threat intelligence, cloud asset correlation, and compliance reporting on top.
This guide compares the best ASM tools available today, covering what each does well, where it falls short, and what it costs. If you want to understand the methodology these tools support, read our guide to mapping your attack surface first.
TL;DR
- ASM tools fall on a spectrum: scanner orchestrators (deep testing), data platforms (broad visibility), and enterprise intel (threat context).
- Small teams should start with combined discovery + scanning tools like Metric Tower or ProjectDiscovery Cloud, supplemented by Shodan for ad-hoc research.
- Internet-scale platforms (Censys, Shodan) find assets your own scans miss -- but they do not test those assets for vulnerabilities.
- Enterprise tools (CrowdStrike, Mandiant) add threat intelligence enrichment but require mature security programs and significant budgets.
- Most organizations benefit from layering tools across categories rather than relying on a single platform.
| Tool | Best For | Key Strength | Pricing |
|---|---|---|---|
| Metric Tower | Discovery + vulnerability scanning | 58 scanners in a unified pipeline | Free tier; Pro/Business |
| Censys | Internet-wide asset visibility | Full IPv4 + certificate database | Free (limited); Enterprise |
| Shodan | Device and service reconnaissance | Powerful search filters + API | Free; from $59/mo |
| PD Cloud | OSS-based managed scanning | Nuclei 11,000+ templates | Free tier; Teams/Enterprise |
| Detectify | Crowdsourced vuln research | Novel attack technique coverage | From ~$278/mo |
| CrowdStrike | Enterprise threat-enriched ASM | Adversary intelligence integration | Enterprise only |
| Mandiant | Threat-centric asset analysis | IR-derived threat group mapping | Enterprise only |
| Assetnote | Continuous exposure monitoring | Fast change detection + JS analysis | Custom pricing |
1. Metric Tower -- Full-Stack Discovery with Integrated Vulnerability Scanning
Metric Tower approaches attack surface management by orchestrating 58 security scanners into a unified pipeline. For asset discovery specifically, the chain starts with passive subdomain enumeration (Subfinder, Amass, CrtSh), adds DNS brute-forcing and permutation (Puredns, Alterx), resolves discovered hosts (Dnsx), scans for open ports (Nmap, Naabu), probes HTTP services (Httpx), and fingerprints technology stacks (WhatWeb, Wafw00f). All discovered assets are tracked in a persistent inventory with monitoring capabilities for DNS changes, SSL certificate expiry, and uptime.
What distinguishes Metric Tower from pure ASM platforms is the integrated vulnerability scanning. After discovery, the same pipeline runs Nuclei, ZAP, Sqlmap, Dalfox, and dozens of other scanners against discovered assets. You get asset discovery and vulnerability assessment in a single workflow, with results tracked over time.
Pros
- Discovery and vulnerability scanning are unified -- no need to export assets to a separate scanner
- 58 scanners provide depth that single-tool platforms cannot match
- Asset inventory tracks changes across scans, showing when assets appear, disappear, or change
- Continuous monitoring for DNS, SSL, and uptime runs alongside periodic deep scans
- Subdomain takeover detection built into the pipeline
- Self-hosted option available for organizations with data sovereignty requirements
Cons
- Does not maintain an internet-scale dataset like Censys or Shodan -- scans on demand rather than pre-indexing
- No cloud asset discovery (AWS, GCP, Azure) through provider APIs -- focuses on external-facing assets
- Threat intelligence enrichment is limited compared to enterprise platforms
Pricing
Free tier available. Pro and Business tiers with credit-based pricing. See pricing page for details.
Best Practice
Start with a combined discovery + scanning tool before adding specialized platforms. Finding assets you did not know about is only useful if you also test them for vulnerabilities -- otherwise you are just building a bigger list of unknowns.
2. Censys -- Internet-Wide Scanning and Certificate Discovery
Censys continuously scans the entire IPv4 address space and maintains a searchable database of every internet-connected host, service, and certificate. Their ASM product uses this data to build an organization's asset inventory automatically by correlating domains, IPs, certificates, and registration data to identify which assets belong to your organization.
The core strength of Censys is data breadth over scanning depth. Because they scan the entire internet independently, they find assets that target-specific scanning misses -- servers on unexpected IP ranges, certificates issued to variant domain names, and services hosted on third-party infrastructure that is associated with your organization through certificate transparency logs or WHOIS data.
Pros
- Internet-scale scanning data that no organization could replicate internally
- Certificate-based discovery finds assets through SSL/TLS relationships, even on non-standard ports
- Cloud connector integrations (AWS, GCP, Azure) for correlating external with internal asset views
- Continuous monitoring with risk scoring and change detection
- Strong research-grade search interface for manual exploration
Cons
- Discovery breadth comes at the cost of scanning depth -- finds assets but does not run vulnerability scanners against them
- Attribution accuracy can produce false positives (incorrectly attributing assets to your organization)
- Enterprise pricing is not accessible for small teams or individual researchers
- Scan frequency is controlled by Censys, not by the user
Pricing
Community tier: free (limited search). ASM platform: enterprise pricing, contact sales. Individual researcher plans from $25/month for search access (as of 2026).
3. Shodan -- The Search Engine for Internet-Connected Devices
Shodan is the original internet device search engine, continuously scanning the internet for open ports and services and making the results searchable. Unlike Censys, which focuses on organizational asset management, Shodan is primarily a research and reconnaissance tool. It excels at finding specific types of exposed devices -- industrial control systems, IoT devices, databases, and misconfigured services -- and provides a powerful query language for filtering results.
Pros
- Comprehensive device and service index with deep banner data
- Powerful search filters (country, organization, product, version, port, vulnerability)
- Shodan Monitor provides continuous tracking of your IP ranges with alerting
- Excellent API with well-documented integrations
- Affordable individual pricing for researchers and small teams
- Real-time alert feed for new vulnerabilities affecting your assets
Cons
- IP-centric rather than organization-centric -- requires you to know your IP ranges already
- No subdomain enumeration or DNS-based discovery
- Limited web application scanning (banner and header data only)
- No vulnerability assessment or remediation tracking
- Scan frequency and depth are not user-controllable
Pricing
Free tier with limited searches. Membership: $59/month. Small Business: $299/month. Enterprise: custom pricing (as of 2026).
Common Mistake
Treating passive data platforms (Censys, Shodan) as a complete ASM solution. These tools tell you what is exposed, but they do not test for vulnerabilities. Pair them with an active scanner to close the loop between discovery and remediation.
4. ProjectDiscovery Cloud -- Open-Source Tools as a Managed Service
ProjectDiscovery is the organization behind many of the most popular open-source security tools: Subfinder, Httpx, Nuclei, Naabu, Katana, and others. Their Cloud platform wraps these tools into a managed service with a web UI, asset tracking, scheduled scanning, and team collaboration features. If you are already using their open-source tools via CLI, the Cloud platform adds persistence, scheduling, and multi-user access.
Pros
- Built on proven open-source tools with active communities and rapid template updates
- Nuclei template ecosystem (11,000+) provides broad vulnerability coverage
- Fast scanning speeds -- ProjectDiscovery tools are built for high-throughput reconnaissance
- Familiar to security researchers who already use the CLI tools
- Generous free tier for individual researchers
Cons
- Less mature as a platform compared to established ASM vendors
- Asset attribution and organization mapping are basic compared to Censys or CrowdStrike
- No internet-scale passive data -- scans on demand like Metric Tower
- Monitoring and alerting capabilities are still developing
Pricing
Free tier for individual use. Teams and Enterprise tiers with custom pricing. Open-source CLI tools are free (as of 2026).
5. Detectify -- External ASM with Crowdsourced Security Research
Detectify combines automated scanning with crowdsourced vulnerability research. Their Surface Monitoring product discovers external assets, and their Application Scanning product tests them for vulnerabilities. The distinctive feature is their Crowdsource program, where independent security researchers submit vulnerability tests that are integrated into the platform, giving Detectify access to novel attack techniques faster than purely internal research teams.
Pros
- Crowdsourced research provides fast coverage of emerging vulnerabilities and novel techniques
- Clean, well-designed UI for asset management and vulnerability tracking
- Good subdomain discovery and monitoring capabilities
- Compliance-friendly reporting and evidence collection
- Integrations with Slack, Jira, Splunk, and other common platforms
Cons
- Limited depth for API-specific testing and custom application logic
- Scanning is less configurable than open-source tool-based platforms
- Pricing can scale quickly with the number of monitored assets
- No self-hosted option
Pricing
Starts at approximately $278/month for Surface Monitoring. Application Scanning is priced separately. Enterprise pricing for large deployments (as of 2026).
6. CrowdStrike Falcon Surface -- Enterprise ASM with Threat Intelligence
CrowdStrike's Falcon Surface (formerly Reposify) provides enterprise-grade external attack surface management backed by CrowdStrike's extensive threat intelligence data. The platform discovers assets, maps them to your organization, identifies vulnerabilities, and enriches findings with threat intelligence showing whether specific vulnerabilities are being actively exploited in the wild.
Pros
- Deep threat intelligence enrichment from CrowdStrike's adversary tracking
- Accurate organizational attribution using multiple data correlation methods
- Integration with the broader Falcon platform (endpoint, cloud, identity) for unified security posture
- Executive dashboards and risk scoring aligned with enterprise reporting needs
- Subsidiary and supply chain asset discovery
Cons
- Designed for large enterprises -- pricing and complexity are prohibitive for smaller organizations
- Primarily discovery and monitoring -- limited active vulnerability testing compared to scanner-based tools
- Full value requires the broader Falcon ecosystem
- Customization and scan configuration are limited
Pricing
Enterprise pricing only. Requires engagement with CrowdStrike sales. Typically sold as part of the Falcon platform bundle (as of 2026).
7. Mandiant Advantage Attack Surface Management -- Google-Backed Threat Intelligence
Mandiant (now part of Google Cloud) brings incident response and threat intelligence expertise to the ASM category. Their platform discovers external assets and enriches findings with Mandiant's threat intelligence, showing which assets match the infrastructure patterns, TTPs, and targeting profiles of known threat groups. This threat-centric view is unique to Mandiant.
Pros
- Threat intelligence from Mandiant's incident response cases and Google's security research
- Identifies assets matching known threat group targeting profiles
- Strong at detecting internet-exposed assets across subsidiaries and acquisitions
- Integration with Google Cloud Security Command Center
- Expert-level analysis capabilities for security operations teams
Cons
- Enterprise-focused with pricing that reflects it
- Discovery depth is narrower than scanner-based platforms for web application vulnerabilities
- Best value comes from pairing with other Mandiant/Google Cloud security products
- Not designed for hands-on security testing workflows
Pricing
Enterprise pricing only, available through Google Cloud or Mandiant sales. Modular licensing available (as of 2026).
Best Practice
When evaluating enterprise ASM platforms, run a proof-of-concept against your actual asset inventory first. Attribution accuracy -- how well the tool identifies which assets belong to your organization -- varies widely and is the single biggest differentiator in practice.
8. Assetnote -- Continuous Security Monitoring and Exposure Management
Assetnote focuses on continuous external attack surface monitoring with an emphasis on detecting exposure changes as they happen. Their platform runs continuous subdomain enumeration, port scanning, and web content monitoring, with alerts triggered when new assets appear, existing assets change, or new vulnerabilities are detected. The platform is built by security researchers with deep offensive experience in bug bounty and red teaming.
Pros
- Strong continuous monitoring with fast detection of new assets and changes
- Built by offensive security practitioners -- the scanning depth reflects real-world attack techniques
- JavaScript analysis and dynamic content discovery for modern web applications
- Good API for integration with existing security workflows
- Acquisition path discovery (finding assets through M&A-related domain and certificate analysis)
Cons
- Less established brand compared to CrowdStrike or Mandiant -- may face procurement friction in large enterprises
- Smaller team means slower feature development in some areas
- No internet-scale passive dataset -- relies on active scanning
- Pricing information is not publicly available
Pricing
Custom pricing. Contact Assetnote sales for quotes (as of 2026).
Choosing the Right Attack Surface Management Tool
The right tool depends on three factors: your organization's size, security maturity, and scope -- whether you need discovery only or discovery plus testing.
Small to mid-size teams: Start with Metric Tower or ProjectDiscovery Cloud for combined discovery and vulnerability scanning. Supplement with Shodan for ad-hoc research and internet exposure checks. This gives you both breadth of discovery and depth of testing at an accessible price point.
Mid-market security teams: Combine Metric Tower or Detectify for active scanning with Censys for passive internet-scale visibility. The overlap is minimal -- Censys finds assets through global scanning data, while Metric Tower/Detectify test those assets deeply for vulnerabilities.
Enterprise security operations: Layer CrowdStrike or Mandiant for threat-enriched ASM on top of a scanning platform. The enterprise tools provide business context, risk scoring, and board-level reporting, while the scanning tools provide the technical depth to actually validate and remediate findings.
Feature Comparison
| Capability | Metric Tower | Censys | Shodan | PD Cloud | Detectify | CrowdStrike | Mandiant | Assetnote |
|---|---|---|---|---|---|---|---|---|
| Subdomain enumeration | Deep | Cert-based | No | Deep | Good | Good | Good | Deep |
| Port scanning | On-demand | Passive | Passive | On-demand | Basic | Passive | Passive | On-demand |
| Vuln scanning | 58 tools | No | CVE tags | Nuclei | Crowdsource | Limited | Limited | Good |
| Threat intelligence | Limited | Some | Some | No | No | Excellent | Excellent | Some |
| Continuous monitoring | DNS/SSL/Up | Yes | Monitor | Scheduled | Yes | Yes | Yes | Yes |
| Cloud integration | No | AWS/GCP/Az | No | No | No | Falcon | GCP | Limited |
| Free tier | Yes | Limited | Limited | Yes | No | No | No | No |
| Self-hosted | Yes | No | No | CLI tools | No | No | No | No |
Key Takeaways
- 1 Scanner orchestrators (Metric Tower, PD Cloud) give you both discovery and vulnerability testing in one workflow -- the best starting point for most teams.
- 2 Internet-scale data platforms (Censys, Shodan) reveal assets your own scanning cannot reach, but require a separate tool for vulnerability assessment.
- 3 Enterprise platforms (CrowdStrike, Mandiant) justify their cost when you need threat intelligence correlation, board-level reporting, and supply chain visibility.
- 4 Layer tools across categories for complete coverage: active scanning for depth, passive data for breadth, and intelligence enrichment for context.
Final Thoughts
Attack surface management is a rapidly maturing category, and the tools reflect different philosophies about what matters most. Scanner-based platforms like Metric Tower and ProjectDiscovery prioritize depth of testing. Data platforms like Censys and Shodan prioritize breadth of visibility. Enterprise platforms like CrowdStrike and Mandiant prioritize threat context and risk reporting.
Most organizations benefit from combining tools across these categories. Use a scanner-based platform for active testing and remediation validation, supplement with a data platform for passive visibility, and add enterprise intelligence if your security program and budget support it. The goal is a complete picture of your attack surface -- what exists, what is vulnerable, and what is being targeted.