Subra vs Halo Security Attack Surface Discovery: 2026 Comparison
Subra is a free external attack surface management tool. Halo Security Attack Surface Discovery is a commercial external attack surface management tool by Halo Security. 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, integrations, company size fit, here is our conclusion:
Security teams running manual subdomain discovery workflows or evaluating attack surface management on a budget should start with Subra; it wraps the open-source subfinder tool in a web interface that cuts the friction of command-line enumeration without requiring infrastructure spend. The 54 GitHub stars and free pricing model mean you can validate subdomain coverage gaps in minutes, not weeks of vendor evaluation. Skip this if you need continuous monitoring, prioritization scoring, or integration with your existing vulnerability management stack; Subra is a one-time discovery tool, not a platform.
Halo Security Attack Surface Discovery
Mid-market and enterprise security teams drowning in shadow infrastructure will find real value in Halo Security Attack Surface Discovery because it actually finds what you don't know you're running, then keeps finding it as things change. The agentless external scanning and automated rescans mean you're catching newly exposed assets and misconfigured domains without adding operational overhead, which directly strengthens your ID.AM and ID.RA posture under NIST CSF 2.0. Skip this if you need internal vulnerability scanning or remediation workflows; Halo stops at discovery and inventory, leaving the actual patching to you.
