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Cybersecurity · head to head

Falco vs Tenable Nessus

Falco logo

Falco

Cybersecurity

CNCF-graduated runtime threat detection for Linux and Kubernetes using eBPF

From
Free
Rated
-
Full reviewWebsite
Tenable Nessus logo

Tenable Nessus

Cybersecurity

Network vulnerability scanner

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Falco falco detects and alerts but does not block; stopping an attack requires wiring up Falco Talon or your own response tooling, so out of the box a confirmed detection still means a human intervening after the fact.; Tenable Nessus nessus Professional is $4,790 for one year, sold as an annual licence rather than a per scan or usage based fee
  • They diverge on capability: Falco covers eBPF kernel instrumentation, Tenable Nessus covers Network scanning.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Falco and Tenable Nessus actually diverge.

Attributes where Falco and Tenable Nessus differ
AttributeFalcoTenable Nessus
Pricing modelOpen source, no licence feesubscription
PlatformsLinux, Kubernetes, Self-hostedWindows, Linux, Macos, Cloud
FoundedUnknown2002

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Cybersecurity).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Falco

  • eBPF kernel instrumentation
  • System call rules engine
  • Container and Kubernetes context
  • Default rule set
  • Falcosidekick
  • Falco Talon
  • Plugins framework
  • DaemonSet deployment

Only in Tenable Nessus

  • Network scanning
  • Vulnerability detection
  • Configuration assessment
  • Malware detection
  • Compliance checking
  • Cloud security assessment
  • Mobile scanning
  • API access

What people use each for

The jobs each tool is most often brought in to do.

Falco

  • A platform team that needs to know when a shell is opened inside a production container, which image scanning cannot detect because it happens at runtimenot Tenable Nessus
  • A regulated business required to evidence host and container intrusion detection on Kubernetes nodes for an auditnot Tenable Nessus
  • A security team wanting a vendor-neutral detection layer whose rules they can read and modify rather than a black-box agentnot Tenable Nessus
  • A cluster where a compromised dependency might write to sensitive paths or open unexpected outbound connections, and only kernel-level visibility will catch itnot Tenable Nessus

Tenable Nessus

  • Vulnerability scanning of servers, network devices and web applicationsnot Falco
  • Configuration and compliance auditing against hardening benchmarksnot Falco
  • Point in time assessments by consultants and penetration testersnot Falco

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Falco

  • Falco detects and alerts but does not block; stopping an attack requires wiring up Falco Talon or your own response tooling, so out of the box a confirmed detection still means a human intervening after the fact.
  • The default rule set is noisy in real clusters and generates a large volume of benign matches from normal operational activity; without weeks of tuning, alert fatigue sets in and the team stops reading the feed, which is the usual failure mode.
  • There is no storage, console, search or case management in the project, so a working detection capability means also running Falcosidekick, an event store, a dashboard and alert routing, all of which you build, host and maintain.
  • The modern eBPF driver requires kernel 5.8 or later; older hosts fall back to the legacy probe or the kernel module, which brings driver-building against kernel headers and the operational fragility that comes with it on every kernel upgrade.
  • Per-node syscall instrumentation carries measurable CPU overhead on busy hosts, and the cost scales with syscall volume rather than with cluster size, so the noisiest and most performance-sensitive workloads are exactly the ones that feel it most.

Tenable Nessus

  • Nessus Professional is $4,790 for one year, sold as an annual licence rather than a per scan or usage based fee
  • Support beyond the base entitlement costs an extra $400 per year for Advanced Support with 24x365 phone and chat access
  • The on demand training course is a separate $275 purchase for a single person for one year
  • Multi year discounts require paying for two or three years up front

Pricing, plan by plan

Falco

Free
  • Falco (open source)Free
    • Apache 2.0 licence, CNCF graduated project
    • eBPF and kernel module drivers
    • Full rules engine and default rule set

Tenable Nessus

Free
  • Nessus EssentialsFree
    • Up to 16 ips
    • Network scanning
    • Vulnerability assessment
  • Nessus Professional$2600/year
    • Unlimited targets
    • Enterprise features
    • Advanced analytics
  • Nessus Expert$5200/year
    • All Professional features
    • Cloud integration
    • Advanced reporting

Which should you pick?

Choose Falco if

  • You need ebpf kernel instrumentation.
  • You want to start without paying.
  • You work on Linux, Kubernetes, Self-hosted.
  • You also want system call rules engine.
Falco review

Choose Tenable Nessus if

  • You need network scanning.
  • You want to start without paying.
  • You work on Windows, Linux, Macos, Cloud.
  • You also want vulnerability detection.
Tenable Nessus review

Questions people ask

Is Falco or Tenable Nessus better?
Neither clearly leads. Falco starts at Free and Tenable Nessus at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Falco or Tenable Nessus?
Falco starts at Free and Tenable Nessus at Free.
Does Falco or Tenable Nessus run on more platforms?
Falco runs on Linux, Kubernetes, Self-hosted. Tenable Nessus runs on Windows, Linux, Macos, Cloud.
Can I use Falco for free?
Both have a free tier, so you can try either at no cost before committing.
What is Falco best used for?
Falco is most often used for a platform team that needs to know when a shell is opened inside a production container, which image scanning cannot detect because it happens at runtime, a regulated business required to evidence host and container intrusion detection on kubernetes nodes for an audit, a security team wanting a vendor-neutral detection layer whose rules they can read and modify rather than a black-box agent, a cluster where a compromised dependency might write to sensitive paths or open unexpected outbound connections, and only kernel-level visibility will catch it. Of those, a platform team that needs to know when a shell is opened inside a production container, which image scanning cannot detect because it happens at runtime and a regulated business required to evidence host and container intrusion detection on kubernetes nodes for an audit are not what Tenable Nessus is typically brought in for.
What can Falco do that Tenable Nessus cannot?
Falco covers eBPF kernel instrumentation, System call rules engine, Container and Kubernetes context, Default rule set. Tenable Nessus covers Network scanning, Vulnerability detection, Configuration assessment, Malware detection.

Answered from the vendors’ own pages

Falco: Does Falco block attacks?

No. It detects and emits events. Response requires Falco Talon or your own automation on top.

Tenable Nessus: What are the three Nessus offerings?

Nessus Essentials is a free introductory offering for educators, students, and career starters, limited to 16 IPs for scanning. Nessus Professional is designed for consultants and SMBs, providing unlimited IT scans across any location. Nessus Expert is the premium offering extending Professional with web application scanning, infrastructure-as-code scanning, and external attack surface assessment up to 5 domains.

Source
Falco: Is Falco owned by Sysdig?

Sysdig created and open sourced it, but it graduated within the CNCF in February 2024, so governance sits with the foundation rather than the vendor.

Tenable Nessus: What OS platforms does Nessus support?

Nessus runs on Debian/Kali Linux, Fedora, FreeBSD, Mac OS X, Red Hat/CentOS, SUSE Linux, Ubuntu, and various Windows versions including Server 2008, 2012, and Windows 7-10.

Source
Falco: What does it cost?

The project is Apache 2.0 with no licence fee. The cost is the storage, routing, tuning and staff time needed to make its output useful.

Tenable Nessus: Can I use Nessus to scan third-party networks as a consultant?

Yes, Tenable permits you to use Nessus to scan third-party networks. Nessus Professional is ideal for consultants.

Source
Falco: What kernel version do I need?

Kernel 5.8 or later for the default modern eBPF driver. Older hosts need the legacy eBPF probe or the kernel module.

Tenable Nessus: Can Nessus perform PCI external scanning?

Yes, you can use Nessus Professional to perform external network scans as required by the PCI DSS 11.2.2 requirement.

Source
Tenable Nessus: What additional features does Nessus Expert provide?

Web application scanning, which is dynamic application security testing (DAST) providing comprehensive visibility and insight into web application security issues; scanning code repositories for vulnerabilities; and assessing external attack surface with subdomain discovery.

Source
Tenable Nessus: What support options exist for Nessus Professional?

Standard Support includes software upgrades, patches, plugin access, and 24x7 support via chat and community portal. Advanced Support adds 24x7 phone access and committed SLAs: P1 less than 2 hours, P2 less than 4 hours, P3 less than 12 hours, P4 less than 24 hours.

Source
Tenable Nessus: How frequently are Nessus plugins updated?

Nessus plugins are updated daily, based on when vendors and security research sites publish new vulnerabilities.

Source
Tenable Nessus: How does licensing work in virtual machine environments?

Whether you are using Nessus in a physical or a virtual environment, the IP addresses or hosts that you are scanning from must be licensed.

Source
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