OpenVAS vs Qualys: What Vulnerability Scanning Should Cost

If you’re reading this, you probably already know vulnerability scanning matters. But in case you need to convince your boss (or yourself), here’s the short version — followed by the part most vendors won’t give you: an honest accounting of what scanning should cost, where the open-source option genuinely wins, and where it doesn’t.

Why vulnerability scanning matters

Your network is a house with hundreds of doors, windows, and secret passages you forgot existed. Every day, attackers learn new ways to get into houses just like yours, and they share those techniques faster than your teenager shares TikTok videos.

According to IBM’s Cost of a Data Breach Report (2024 edition), the global average breach cost reached $4.88 million USD. For Canadian small and medium businesses, even a “small” incident routinely lands in the six figures once response, downtime, and notification costs are counted — and many small businesses never fully recover financially from a major cyber attack.

Vulnerability management has three pillars:

• Discovery: You can’t protect what you don’t know exists. Scanners find all your assets, including that IoT coffee maker someone plugged in without telling IT.
• Assessment: Every asset gets checked against a database of known vulnerabilities — like comparing your locks against the list of locks burglars have already learned to pick.
• Prioritisation: Some findings are an open front door; some are a loose latch on the third floor. Good scanning tells you which to fix first.

What commercial scanners cost

Commercial scanner pricing is mostly quote-driven, so treat every figure here as published list pricing (2024–2025 list rates; real contracts often come in below list — verify against your own quotes). Consistent with the comparison we publish on our managed OpenVAS page:

• Qualys VMDR: roughly $199–$250 USD per asset per year at list, plus scanner appliances commonly quoted around $8,000–$9,000 per year each. Per-asset pricing is predictable but adds up quickly as your estate grows.
• Tenable Nessus Professional: $4,790 USD per year per scanner with unlimited IPs — genuinely the cheapest serious commercial scanner if one engineer is going to run scans by hand. The centrally managed Tenable SKUs (Tenable Vulnerability Management, Security Center) are quote-driven and considerably more expensive.
• Rapid7 InsightVM: roughly $1.93 USD per asset per month at the 500-asset tier, per published list pricing.

Note what those licence fees don’t include: someone to schedule the scans, tune the false positives, chase the remediation tickets, and package the evidence for your auditor. The licence is the cheap part.

What OpenVAS’s 95,000+ tests cover

OpenVAS (the scan engine behind Greenbone’s vulnerability management stack) ships with 95,000+ community-feed tests — Greenbone’s published aggregate — updated daily at no licensing cost. For compliance-bound scopes we deploy the Greenbone Enterprise Feed, which carries 200,000+ tests, ships updates multiple times a day, and covers enterprise products (Cisco, Exchange, Palo Alto) the community feed explicitly doesn’t.

To be honest about the competitive landscape: Tenable and Qualys ship larger check libraries, and Tenable in particular is faster at shipping checks for novel CVEs. OpenVAS’s coverage is competitive where most SMBs actually live. What the tests cover:

• Operating system vulnerabilities: missing patches and end-of-life software across Windows, Linux, and macOS. It’s common in real environments: organisations that have “patched everything” still have forgotten DMZ servers vulnerable to years-old exploits like EternalBlue.
• Network service vulnerabilities: every service is a potential entry point — SSH, FTP, SMB, RDP, DNS, SMTP, and hundreds more. Anonymous SMB shares that were “internal only” until someone exposed them to the internet are a perennial classic.
• Web-layer weaknesses: OpenVAS covers many common web-layer weaknesses — outdated server software, dangerous defaults, TLS misconfiguration — plus CMS-specific tests for WordPress, Joomla, Drupal, and SharePoint. It is not a full web-application scanner, which matters (see “Where OpenVAS doesn’t fit” below).
• Compliance content: CIS Benchmark checks and the scan evidence that PCI DSS Requirement 11.3 (11.2 in v3.2.1), SOC 2, ISO 27001, and HIPAA audits ask for.

What managed OpenVAS adds

The catch with OpenVAS — like most open-source security tools — is that it’s not plug-and-play. Most companies either give up and buy Qualys, or set it up poorly and wonder why it isn’t working. “Managed” means we own that problem. Here’s what it looks like in practice:

Phase 1: Setup and onboarding

• Discovery call to understand your infrastructure and segmentation
• Deploy the scanning infrastructure in your environment
• Configure authenticated (credentialed) scanning — the difference between checking the locks and checking inside the house
• Initial baseline scan with manual false-positive tuning, targeting a sub-5% false-positive rate

Phase 2: Continuous operations

• Daily: critical production systems and internet-facing assets
• Weekly: internal infrastructure and development environments
• Monthly: full comprehensive deep scans
• New-CVE rescans when something like Log4Shell drops — continuous scanning is the difference between knowing your exposure within a day and finding out at next quarter’s scan

Phase 3: Analysis and reporting

Raw scanner output is useless to most teams. What you get instead reads like this:

CRITICAL: Your customer portal is vulnerable to remote code execution. What: The web server hosting your customer portal is running an outdated version of OpenSSL with a known critical vulnerability that attackers are actively exploiting. Impact: An attacker could take control of this server, steal customer data, or use it as a launching point for further attacks. Fix: Update OpenSSL to the patched version. We’ve attached the exact commands for your Ubuntu system.

Findings flow into your ticketing system, and a monthly executive report plus compliance pack covers the audit side.

Where OpenVAS doesn’t fit

An honest comparison has to include the cases where we’d point you elsewhere:

• PCI external scans require a certified ASV. PCI DSS mandates that quarterly external scans be performed by an Approved Scanning Vendor — a certification OpenVAS deployments don’t carry. Managed OpenVAS covers your internal scanning requirement and day-to-day vulnerability management; for the external ASV scans, we coordinate with a certified ASV so both boxes are ticked. Any vendor telling you OpenVAS alone satisfies PCI external scanning is giving you compliance advice that will fail your assessment.
• Deep web-application testing. OpenVAS finds web-layer misconfigurations and known-vulnerable components, but it won’t find injection flaws in your custom code or broken business logic the way a dedicated DAST tool or a penetration test will. Scanning and pentesting answer different questions.
• Cloud-native, ephemeral estates. If your environment is dominated by short-lived cloud workloads with no static network plan, an agent-based platform or CSPM is a better shape than any network scanner — including OpenVAS. We’ll say that out loud in the discovery call.

A worked cost example

Explicitly hypothetical model — illustrative figures, not a client engagement. Take a 150-asset organisation: a typical small manufacturer or professional-services firm.

• Qualys VMDR at list: 150 assets × $199–$250 USD/asset/year ≈ $30,000–$37,500 USD per year, before scanner appliances and before anyone on your team spends an hour triaging results.
• Nessus Professional DIY: $4,790 USD per year for the licence — plus the real cost, which is the fraction of an engineer’s time spent scheduling, tuning, triaging, and reporting. At even 20% of a $100K engineer, that’s another ~$20,000 of hidden run cost.
• ThinSky Managed OpenVAS: the engine is free; you pay for senior-engineer operation — scheduling, tuning, triage, ticketing integration, and audit-ready reporting. Pricing is quoted against your actual asset inventory rather than a per-asset metre: request a quote.

The pattern that holds across estate sizes: with open source, your money buys operation instead of licences. Whether that trade wins for you depends on your asset count and how much scanner operation your team wants to own — which is exactly what a scoping call settles. (For the broader story of open-source tools displacing commercial security suites, see how open source is eating enterprise security.)

FAQ

Is OpenVAS as good as Nessus or Qualys?

Honestly: not on every axis. Tenable ships larger plugin libraries and is faster on novel CVEs; Qualys has stronger cloud-agent coverage. For internal posture work on a standard Linux-plus-common-services estate, OpenVAS is usually a match — and on the Greenbone Enterprise Feed (200,000+ tests) it covers compliance-bound and enterprise-product scopes too. The right comparison isn’t engine vs engine, it’s outcome vs outcome: tuned scans, triaged findings, and audit evidence, at what total cost.

Does OpenVAS meet PCI DSS scan requirements?

For internal scans (Requirement 11.3.1 in PCI DSS v4.0): yes, managed OpenVAS produces the quarterly internal scan evidence assessors expect. For external scans: no scanner you run yourself can — PCI requires those be performed by a certified Approved Scanning Vendor. We coordinate with an ASV for the external scans and run everything else, so your PCI scanning evidence is complete.

How much does managed vulnerability scanning cost for a small business?

It depends on asset count, segmentation, and compliance scope, which is why we quote against your real inventory instead of publishing a one-size tier. As reference points, commercial per-asset platforms list at roughly $200–$250 USD per asset per year before operations. Managed OpenVAS replaces licence spend with engineering — request a quote and you’ll get a number, not a sales cycle.

How often should we scan?

Internet-facing and critical systems: daily or weekly. Internal infrastructure: weekly to monthly, with a monthly full deep scan. Always rescan after significant changes and when a major CVE drops. Quarterly-only scanning leaves you exposed for an average of 45 days per new vulnerability — and your auditor will want to see a defined cadence, not ad hoc scans.

See what you’re exposing first

The cheapest first step costs nothing: ThinSky’s free passive assessment at /audit/ shows you what your organisation already exposes to the internet. If the results make the case for continuous coverage, our managed OpenVAS service takes it from there — tuned scanning, plain-English reporting, and compliance evidence, scoped and priced to your environment. For deeper testing beyond scanning, see automated penetration testing, or talk to us directly at /contact/ or sales@thinsky.com.