Noxen vs Tenable Nessus

Tenable Nessus is the reference scanner that every other scanner is implicitly compared against. It has the deepest plugin library, the most authoritative CVE coverage, and a credentialed-scan story good enough that auditors will accept its output without an argument. None of that is a problem Noxen tries to solve. We are not pretending to be Nessus. We are pretending to be the right size for the people Nessus is too much for.

What Nessus is

Tenable Nessus is a credentialed network vulnerability scanner with a plugin library going back to the late 1990s — well over 200,000 individual checks, with new ones added every week. Nessus Professional runs locally on a Linux or Windows box with a Java-backed web UI; Tenable.io is the SaaS sibling; Tenable.sc is the on-prem enterprise console. Public pricing for Nessus Professional sits around $4,000–$5,000 per year and scales up from there. It is the tool you buy when an auditor or insurance underwriter has named it by product name on a control sheet.

When Nessus is the right choice

• You have a compliance binder. PCI-DSS, HIPAA, FedRAMP, SOC 2 Type II with a particular auditor — these are worlds where Nessus output is the default evidence format. Noxen's compliance mapping is evidence supplement, not certification. Nessus is the right shape for that requirement.
• You need deep web-application scanning. Tenable Web App Scanning (and Nessus's older WAS plugins) cover OWASP-Top-10-class checks, JavaScript crawling, and authenticated app testing. Noxen does HTTP security headers and admin-surface fingerprinting only.
• Your fleet is thousands of hosts. Nessus scales horizontally with scanner appliances and a central console. Noxen tops out at 500 hosts on the MSP tier.
• You scan Windows, network gear, ESXi, and OT equipment. Nessus's plugin coverage of Windows patches, Cisco/Juniper/Palo Alto IOS images, VMware ESXi, and SCADA gear is unmatched. Noxen scans Linux / Unix / BSD over SSH and stops there.
• You already have a Tenable, Rapid7, or Qualys contract. Adding a second scanner is rarely the right move. Use what you have.

When Noxen is the right choice

• Your fleet is six to fifty Linux hosts. Homelab, prosumer, indie SaaS, small agency — the shape Nessus Professional is over-engineered for and Tenable Essentials is feature-gated against.
• $4,000-plus per year for a scanner is not a sensible line item. Noxen 1.x is $79 one-time. Live Feed is $19/mo if you want a daily feed instead of per-release snapshots. Maintenance is $39/yr from year 2 and is optional — the app keeps running if you skip it.
• You want a Mac-native UI, not a Java web console. Noxen is a SwiftUI app. ⌘N to add a host. ⌘⇧P for the command palette. ⌘R to scan. It feels like a Mac app, because it is one.
• You want the diff, not the firehose. Nessus reports every finding on every host every time. Noxen defaults to what changed since yesterday. The full inventory is one click away when you want it.
• You want your scan data to stay local. No SaaS round-trip, no Tenable.io account, no third party seeing your host list. Noxen's servers only host the signed CVE feed.

We've written more on this framing in Nessus alternative for Mac homelabs — Nessus is a Mercedes; for a one-block commute, you want a bicycle.

Side-by-side

What we don't try to be

Noxen is not a Nessus replacement at enterprise scale. It does not scan Windows. It does not perform web-application testing beyond HTTP header checks. It does not test default credentials against the admin surfaces it finds. It is not a continuous always-on SaaS monitor. The compliance mapping is for handing to your auditor as supporting evidence, never as the primary compliance claim. If those gaps matter for your job, Nessus is the right call — and we are saying that without irony.