Assetnote ASM vs Knock: 2026 Comparison
Assetnote ASM is a commercial external attack surface management tool by Assetnote. Knock 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.
Security teams doing external attack surface reconnaissance on a budget should start with Knock; it's free, it works, and the 4,054 GitHub stars reflect actual adoption rather than marketing hype. The tool excels at the narrow job of subdomain enumeration, which maps NIST Govern and Identify functions by forcing you to know what's actually exposed before you can defend it. Skip Knock if you need continuous monitoring or API integration into your existing ASM stack; this is a point-in-time scanner you run manually, not a platform that feeds ongoing discovery into your risk register.
