OpenVAS — the scan engine behind Greenbone — is the grandfather of open-source vulnerability scanning. A signed feed of tens of thousands of network vulnerability tests, a serious scan engine, and the closest thing open source has to a Nessus equivalent. If your requirements say "comprehensive vulnerability scanning" and your budget says "free," OpenVAS is on the shortlist, and our OpenVAS tutorial covers the self-hosted setup.
This page is about the other path: running OpenVAS-style scanning — or a modern equivalent — without operating the infrastructure yourself.
What self-hosting OpenVAS actually costs
"Free" software with real requirements. The honest operating costs:
- Footprint. A usable Greenbone installation wants dedicated hardware or a fat VM — multiple GB of RAM minimum, more for concurrent scans — plus storage for feed data and results.
- Feed syncs. The vulnerability feed updates daily and the sync must work, every day, or your scanner quietly goes stale. Feed failures are the most common way self-hosted OpenVAS instances rot.
- Setup time. First-time deployments regularly eat days: appliance choice, feed initial sync (hours on its own), user setup, scan configuration, target lists.
- Tuning. Out of the box, scans are slow and noisy. Credentialed checks, scan windows, and false-positive triage all need an owner.
- Upgrades. Version upgrades are non-trivial enough that many operators skip them, which starts the staleness clock again.
None of this is a criticism of the software — it's enterprise tooling with enterprise operational weight. It's just that most teams evaluating OpenVAS want the scanning, not the second job.
What a hosted alternative changes
A hosted vulnerability scanning platform moves the engine, the feed, and the operations to someone else's problem:
- No infrastructure. No VM, no feed sync, no upgrades. You pick a target and scan.
- Fresh detection by default. The provider owns keeping detection current. If their feed is stale, that's visible in your results and you can leave — a market pressure self-hosted installs never face.
- Parsed results. Raw OpenVAS output is famously dense. A hosted platform should hand you severity-rated, deduplicated findings rather than a raw report dump.
- Safe egress. Scans originate from the provider's dedicated infrastructure — not your office IP, not a production box, no firewall exceptions to negotiate.
- Reporting. If results need to reach a client or leadership, the platform's report engine does the formatting work a raw scanner never will.
The Nuclei question
Here's the part most "hosted OpenVAS alternative" pages won't tell you: depending on what you're scanning, you may not want OpenVAS-style scanning at all.
OpenVAS is breadth-first over network services, driven by a version- and behavior-based feed. If your targets are web-exposed — websites, APIs, cloud-hosted apps, which is most external attack surface these days — template-driven scanning with Nuclei is faster, updates within days of new public exploits, and produces cleaner evidence (the actual HTTP exchange that proved the issue). Version-based feed checks, by contrast, inventory-then-match, which surfaces more false positives on web stacks and says nothing about the application itself.
That's why VulnScanners runs Nuclei rather than OpenVAS for CVE and exposure detection, with Nmap doing the service mapping underneath and OWASP ZAP covering web application testing. For internet-facing targets, this stack finds the practically-exploitable issues with far less noise. Our open source CVE scanner guide compares the detection approaches in detail, and the best open-source vulnerability scanners comparison places all the engines in one stack.
When to still run real OpenVAS
Honesty section, as always:
- Internal networks. Hosted external scanning can't reach inside your perimeter. If you need credentialed scans of internal hosts, an on-prem OpenVAS (or an agent-based commercial product) is the right tool.
- Compliance mandates. Some frameworks specifically require feed-based authenticated scanning. If a control maps to that, map the control first.
- Large flat networks. Hundreds of heterogeneous internal hosts with mixed legacy services is OpenVAS's home turf.
For everything else — external surface, client-facing assessments, recurring checks on cloud-hosted infrastructure — a hosted platform covers the use case without the second job.
See it on your own target
The practical test is the same as always: scan something you own and judge the output. VulnScanners runs the hosted pipeline — Nmap mapping, Nuclei CVE and exposure checks, ZAP web testing — and delivers severity-rated findings plus a client-ready PDF report, priced per scan with no subscription. Run a free scan and compare it to what your OpenVAS instance (or your imagination of operating one) gives you.