Wazuh vs Splunk comes down to what you are short of: money or people. Splunk gives you a mature product and charges by the volume you put through it. Wazuh gives you the source, charges nothing for it, and expects you to supply the engineering. The same axis explains most of the comparison against Elastic Security, and a different axis entirely explains Security Onion and OSSEC, which solve narrower problems.

This lesson is a buying decision aid, not a scoreboard. No pricing appears here, from any vendor, because published list prices rarely survive contact with a procurement conversation.

What you need

The comparison at a glance

Wazuh Splunk Enterprise Security Elastic Security Security Onion OSSEC
Licence model Free and open source, GPLv2 and AGPLv3 Commercial, proprietary Mix of open source and source-available licences; some security features in paid tiers Free and open, distributed by Security Onion Solutions Free and open source, GPLv2
Own endpoint agent Yes, one agent for Linux, Windows, macOS Universal Forwarder, log shipping focused Elastic Agent, endpoint security in paid tiers Uses Elastic Agent and network sensors Yes, host-based only
Network sensor No Via add-ons Via integrations Yes, Suricata and Zeek in the box No
Detection model Sigma-format rules evaluated by detectors in the indexer SPL searches and correlation searches Detection rules in the detection engine, Sigma import possible Suricata signatures plus Elastic detections XML rules in the manager
Endpoint state (FIM, inventory, posture) Built in Add-on or third party Partly, in paid tiers Via the Wazuh or Elastic agent File integrity and rootcheck only
Main cost driver Engineering time and infrastructure Licensed data volume or workload Tier and node count Infrastructure and engineering time Engineering time
Scale ceiling Manager cluster plus indexer cluster; documented multi-node deployments Very high, with indexer clustering Very high Practical limit is sensor throughput and storage Small; single manager
Who typically runs it Internal security team or a service provider Enterprise SOC with a platform team Teams already invested in the Elastic stack Network-focused teams and analysts Individuals and small estates

Licence terms and tier boundaries change. Check each vendor’s current terms before you build a business case on this table.

Wazuh vs Splunk

Splunk’s strength is the search experience and the ecosystem around it. SPL is expressive, the app catalogue is large, and there is a deep bench of consultants and analysts who already know it. If your team has Splunk skills, moving away from them destroys real value.

Its weakness, for most organisations, is that the pricing model puts you in a permanent argument with yourself about what to ingest. Teams stop sending verbose sources to save volume, and then discover during an incident that the source they dropped was the one that mattered. That behaviour is the hidden cost.

Wazuh inverts this. There is no licence penalty for ingesting more, so the constraint becomes disk and indexing throughput, which you can reason about with arithmetic rather than a renewal negotiation. In exchange you own the uptime, the upgrades, the certificate rotations and the detection content.

The comparison that decides it is rarely feature by feature. It is whether you can staff a platform. If the answer is that one person will do it alongside four other roles, Splunk’s operational simplicity earns its cost.

Wazuh vs Elastic Security

These two sit closest together, and Wazuh 5.0 moved them closer still.

In Wazuh 4.x, detection was a manager-side engine with XML rules, and the Elastic comparison was easy to draw: one product had SIEM-native detection rules running against an index, the other had a log analysis daemon with its own syntax. In 5.0 that distinction largely goes. Rules are Sigma-format YAML, they carry mitre and compliance blocks as first-class structure, and they are evaluated by detectors scheduled inside the indexer against normalised documents. Anyone who has written detections against an Elasticsearch or OpenSearch index will find the shape familiar. The detection engineering lesson goes into what the Sigma implementation supports.

Two real differences remain.

Endpoint scope. The Wazuh agent does file integrity monitoring, configuration assessment, inventory collection, vulnerability data and response execution as standard, on Linux, Windows and macOS, with no tier gating. Getting the same breadth from Elastic usually means a paid tier.

Licensing predictability. Wazuh’s components are GPLv2 and AGPLv3, stated plainly in the official documentation. Elastic’s licensing has changed more than once in recent years, and which features sit in which tier is worth re-checking at the moment you decide.

Wazuh vs Security Onion

This is the comparison people most often get wrong, because the two products barely overlap at the sensor layer.

Security Onion is a distribution. It bundles network intrusion detection, protocol metadata and packet capture with a search back end and an analyst interface. Its centre of gravity is the wire. Wazuh has no network sensor at all. It sees what an endpoint or a log source tells it.

So the question is not which to pick, it is which visibility gap hurts more. If you have unmanaged devices, OT segments or anything you cannot install an agent on, network visibility is not optional and Wazuh will not give it to you. If your estate is laptops and cloud workloads, network capture buys you less than endpoint telemetry per pound of effort.

Running both is common and reasonable. The usual pattern is to keep network detections where they are generated and forward the interesting ones into the platform that holds endpoint context, so an analyst has one place to pivot.

Wazuh vs OSSEC

Wazuh began as a fork of OSSEC and the two have been diverging for a decade. OSSEC today is a host intrusion detection system: an agent, a manager, XML rules, file integrity monitoring and rootcheck. It is small, it is stable, and it does not pretend to be a platform.

Wazuh added everything around that core: an indexer, a dashboard, a management API, RBAC and single sign-on, vulnerability detection fed from a threat intelligence service, configuration assessment, cloud log collection and a content management system for detection rules.

If somebody is choosing between them in 2026, the question is usually whether they want a platform at all. For a handful of hosts and a person who will read the alerts by email, OSSEC is defensible. For anything that needs search, dashboards, multiple operators or an audit trail, it is not.

When not to pick Wazuh

The uncomfortable section. I have talked more than one organisation out of deploying it.

You cannot name an owner. If no named person has time allocated for tuning in the first quarter, you will end up with an expensive log archive that nobody trusts. Alert fatigue arrives in about six weeks.

You need network visibility above all. Covered above. Buy or deploy a network sensor first.

Your compliance requirement is for a specific named product. Some regulated procurement processes name tooling. Arguing with that is rarely a good use of energy.

You need certified vendor support with contractual response times and your organisation will not buy it. Commercial support for Wazuh exists. If the policy is that production platforms must carry support, and the budget for it does not, that is a genuine blocker rather than a technical one.

You are about to standardise on 5.0 and you depend on a 4.x capability that is gone. The manager syslog listener, integratord scripts, XML rules, CDB lists and the per-module PDF reports are all removed, and manage_agents no longer appears in the manager’s tools reference. The 5.0 change inventory lists the lot. If one of those is load-bearing for you, plan the replacement before you commit.

You want multi-tenant separation today, in the beta. Document-level security is not documented for 5.0 as of September 2026, so if strict tenant isolation is a hard requirement, treat it as unproven until general availability. The multi-tenancy lesson sets out the pattern and what to verify.

Common errors

The proof of concept is sized on alert volume, not event volume

Symptom: the pilot runs fine on a small box and the production deployment falls over on disk or ingest. In Wazuh 5.0 every event is indexed, not just the ones that match a rule, so the volume arriving at the indexer is far larger than the 4.x alert stream people are used to estimating from. Size against events per second and default retention. The sizing lesson shows the arithmetic.

A community Sigma rule is imported and never fires

Symptom: the rule saves cleanly, the detector runs, no findings appear. The field names in a community Sigma rule follow whatever schema its author used. Wazuh validates and evaluates against the Wazuh Common Schema, so EventID has to become event.code, SourceIp has to become source.ip, and so on. Mapping the fields is the work, not the import.

Rules are migrated from 4.x by copying files

Symptom: the manager will not start, or the content never loads. There is no supported path for copying 4.x rules, decoders or lists into a 5.0 installation, and the manager treats unknown configuration elements as a startup error. Custom content is re-authored through the content management system.

Two SIEMs end up ingesting the same sources during a bake-off

Symptom: doubled agent load on endpoints and confusing duplicate findings. Run the comparison on a representative subset of hosts rather than the whole estate, and decide in advance which platform owns response during the trial so nothing gets actioned twice.

Where to read the primary source

Wazuh’s own licence statement and component overview are on the Wazuh 5.0 quickstart page, and the detection model that changes the Elastic comparison is described in the data analysis documentation. Wazuh 5.0 is in beta as of September 2026, with beta5 published on 1 September and no general availability date announced, so anything you benchmark now should be re-checked at release.

Next: Wazuh system requirements and sizing.

Frequently asked questions

Is Wazuh a SIEM?

Yes, with endpoint capabilities layered on top. It centralises logs, indexes them, searches them and raises findings against detection rules, which is the working definition of a SIEM. It also collects endpoint state such as file integrity, inventory and configuration assessment, which most pure SIEMs do not.

Is Wazuh better than Splunk?

Different trade. Splunk buys you a mature search language, a large app ecosystem and vendor support, and you pay for volume. Wazuh costs you engineering time instead of licence spend and gives you endpoint collection in the same product. If your bottleneck is skilled staff time, Splunk usually wins. If it is budget with staff available, Wazuh usually wins.

What is the difference between Wazuh and OSSEC?

Wazuh began as a fork of OSSEC and has since diverged completely. OSSEC is a host intrusion detection agent with a small manager. Wazuh adds an indexer, a dashboard, a management API, vulnerability detection, configuration assessment, cloud log collection and a full detection engine. If you are choosing today, OSSEC only makes sense where you want a minimal HIDS and nothing else.

Can Wazuh replace Security Onion?

Only partly. Security Onion bundles network sensors and packet capture alongside a search back end, and Wazuh has no network sensor of its own. Many teams run both and send the network detections into Wazuh, or run Security Onion for network visibility and Wazuh for endpoints.

Does Wazuh 5 change how it compares to Elastic Security?

It narrows one gap. Detection rules in Wazuh 5.0 are written in Sigma format and evaluated inside the indexer, which is a familiar model for anyone who has used detection rules in an OpenSearch or Elasticsearch based stack. The remaining differences are the endpoint agent scope, the licensing model and the size of the commercial ecosystem.