Assetnote ASM vs SubOver: Side-by-Side Comparison (2026)
Features, pricing, ratings, and pros & cons — compared head-to-head.
Assetnote ASM is a commercial external attack surface management tool by Assetnote. SubOver is a free external attack surface management tool. Compare features, ratings, integrations, and community reviews side by side to find the best external attack surface management fit for your security stack.
CST VerdictBased on our analysis of NIST CSF 2.0 coverage, core features, company size fit, deployment model, here is our conclusion:
Mid-market and enterprise security teams managing sprawling external infrastructure will get the most from Assetnote ASM because its hourly asset discovery actually catches exposures before your business units spin up new services, not weeks after. The platform covers ID.AM and DE.CM across NIST CSF 2.0, meaning you're building a real asset inventory while monitoring it continuously, and the exploit-based verification eliminates the noise that buries actionable findings in traditional scanners. Skip this if your organization lacks the headcount to operationalize a workflow-driven program; Assetnote's strength is enabling lean teams to prioritize, not giving you a dashboard to ignore.
Penetration testers and bug bounty hunters will move fast with SubOver because it automates subdomain enumeration and takeover detection without the setup overhead of commercial platforms. The tool has nearly 1,000 GitHub stars and costs nothing, making it the obvious first pass before you escalate to manual verification or paid scanners. Skip this if you need continuous monitoring integrated with your attack surface management stack; SubOver is built for one-off assessments, not persistent surveillance of your DNS posture.
