Noxen vs OpenVAS / Greenbone

OpenVAS — these days packaged as Greenbone Community Edition, under the broader Greenbone Vulnerability Management (GVM) umbrella — is the open-source elder of network vulnerability scanners. Free, capable, deeply customisable. Also: a 4-container Docker stack, a Postgres database, a feed sync that takes hours on first run, and a web UI you will be talking to for the rest of the relationship. The trade-off is real. Let's name it.

What OpenVAS is

OpenVAS is the scanner engine; Greenbone Community Edition is the packaging; GVM is the management framework around it. It runs on Linux as a stack of services (scanner, manager, GSA web UI, Redis, Postgres). The vulnerability feed — Network Vulnerability Tests (NVTs) — is community-maintained and synced via Greenbone's feed-sync tooling. The community feed contains well over 100,000 NVTs and grows weekly. Greenbone Enterprise is the paid sibling with a deeper, faster-updated feed and vendor support.

When OpenVAS is the right choice

• The licensing cost has to be zero. Academic, research, public-sector budget-zero contexts. OpenVAS is GPL-licensed. You can run it forever for free.
• You want the source. Audit it. Fork it. Write your own NVTs in NASL. OpenVAS is hackable in a way that no commercial scanner is.
• You're already running a Linux server. If you have a homelab Proxmox box with spare capacity, standing up a Greenbone container stack is a reasonable evening.
• You want broad network coverage out of the box. NVTs cover Windows, Linux, network gear, and a long tail of services. Noxen covers Linux/Unix over SSH plus admin-surface fingerprinting on ~70 services. Different scope.
• You want unauthenticated network scanning. OpenVAS is built around that. Noxen is built around credentialed SSH scanning; the port scan is a small part of what it does.

When Noxen is the right choice

• Your time is more expensive than $79. OpenVAS first-run sync routinely takes hours. Tuning false positives is its own minor career. Noxen sets up in under ten minutes and the feed is a signed SQLite snapshot that downloads in seconds.
• You want a Mac-native control plane. Noxen is a SwiftUI app. OpenVAS is a Linux web UI; the Mac is just a browser tab in that relationship.
• You don't want to run another server. Noxen runs on your existing Mac. Your scan target list is read from ~/.ssh/config. There is nothing else to host.
• You want curated coverage instead of a firehose. OpenVAS will tell you everything it can think of. Noxen makes opinionated choices — package CVEs, SSH config, TLS, HTTP headers, ~70 admin surfaces — and ships a UI that defaults to what changed since yesterday.
• You want a signed, reproducible feed. Noxen's feed is an Ed25519-signed SQLite snapshot from VulnCheck NVD++ and OSV (with GHSA on the ingest side). The Mac verifies the signature with CryptoKit before swapping the local copy. OpenVAS's NVT sync is rsync-based; integrity rests on transport trust.

Side-by-side

What we don't try to be

Noxen is not open source. The CVE feed is signed and built by us; you cannot fork our ingest pipeline and run it locally. We do not let you write custom NASL plugins — the closest thing is the custom checks system, which is a small JSON schema for HTTP/TCP probes, not a full scripting environment. Noxen does not scan Windows. It does not do continuous SaaS monitoring. The compliance mapping is evidence supplement, not a certification. If any of those gaps matter, OpenVAS / Greenbone is genuinely the better tool.

For more on why we picked credentialed SSH scanning over network probing, see agent vs agentless security scanning.