Which fits your network visibility needs: QRadar or Security Onion?
QRadar fits when the team wants a packaged SIEM, already has QRadar rules, reports and DSM-based log onboarding, and values vendor support on its on-premises product, which IBM continues to provide after the SaaS business moved to Palo Alto Networks. Security Onion fits when network-centric detection is the priority: it bundles Suricata for intrusion detection, Zeek for protocol metadata and Suricata full packet capture, and it installs from ISO media for networks without internet access. The decision turns on three questions. First, how much weight does the team put on network flows and packet data compared with log-based SIEM correlation? Second, can the team accept the Elastic License 2.0 terms, which make Security Onion source-available rather than OSI open source, and check them with counsel if you embed or resell it? Third, does the staff have the capacity to run a distributed deployment of manager, sensor and search nodes?
Before you decide, check how your QRadar flow licensing maps to what you actually collect. Inventory which flow sources, packet visibility points and sensor placements you need, and compare that with the hardware minimums in the Security Onion hardware documentation, which also note that Security Onion supports only x86-64 processors. Confirm which Security Onion release fits your operating system plan, since the 3.0.0 line supports only Oracle Linux 9. Also confirm how QRadar's offenses and rules would map to Suricata NIDS rules and Sigma rules managed in the Security Onion Console. Many teams find the answer is a hybrid: Security Onion for network telemetry alongside a log-based platform for endpoint and application events. Ask whether your use case needs the Security Onion Pro features, such as OIDC single sign-on or FIPS mode, and price those separately from the free edition.
Which platform fits which scenario
This table compares QRadar on premises with Security Onion across common decision drivers for network-focused security teams. Read each row as a condition you can test in your own environment, then check the named fit against your sizing, staffing and licensing requirements before choosing.
| Scenario | Better fit | Reason |
|---|---|---|
| Network flow analysis is the main need | Security Onion | Security Onion bundles Suricata, Zeek and Suricata full packet capture, which covers network visibility beyond flow records. Confirm the sensor placement you need. |
| Large existing QRadar content and analyst skills | QRadar on premises | Offense rules, AQL searches and analyst workflows already exist in QRadar. Moving them to Security Onion requires rebuilding detections in its Console and Sigma and Suricata rules. |
| Air-gapped sites | Security Onion | Security Onion supports full installs without internet access, with the ISO carrying packages and NIDS, YARA and Sigma rules. Confirm how your update process will handle new ISO media. |
| Team without Linux cluster operations experience | QRadar on premises | A distributed Security Onion deployment runs manager, sensor and search nodes that your team must operate. Confirm whether you need outside support or a Security Onion Pro tier. |
| Need for OSI-approved open-source licensing | Wazuh or OpenSearch-based stacks | The Security Onion repository is licensed under the Elastic License 2.0, which is source-available rather than OSI-approved. Wazuh is GPLv2 and OpenSearch is Apache 2.0. |
| Need for an on-premises SIEM with a broad log source catalog | QRadar on premises | QRadar's log source support is built around its DSM ecosystem. Security Onion centers on network telemetry and Elastic Fleet agents, so confirm coverage for your specific log sources. |
| Strong demand for full packet capture in production | Security Onion | Security Onion replaced Stenographer with Suricata for full packet capture in version 3.0.0. Confirm storage sizing with your sensor design before committing. |
| Distributed design with a single manager dependency | Plan for it either way | Per the Security Onion architecture docs, search nodes stop indexing if the manager is down. Ask both vendors and integrators how redundancy is built into your design. |
What the Elastic License 2.0 means for Security Onion
The Security Onion repository is licensed under the Elastic License 2.0 (ELv2), which is a source-available license rather than an OSI-approved open-source license. In practice, that means you can read the source and, under the license terms, use the software for your own internal security monitoring. The license does not give the same freedoms that Apache 2.0 or GPLv2 give, so the terms matter more here than they would for a permissively licensed SIEM component. Before you standardize on Security Onion, have counsel read the Security Onion repository license file and confirm how the terms apply to your intended use, including modification and redistribution.
Three questions deserve a written answer from counsel. First, does your planned use count as internal use of the software for your own organization's security operations? Second, do you intend to modify Security Onion code or ship a modified build to other parties, such as a subsidiary, a customer or a managed security provider? Third, would any service you offer to third parties, such as monitoring or hosting Security Onion for clients, fall under restrictions that the license places on providing the software as a managed service? Your answers decide whether the free distribution is enough or whether you need a commercial arrangement with the vendor. Do not assume that the license is interchangeable with the open-source licenses used by your other tools.
The free distribution and Security Onion Pro, the paid tier, are not the same product in terms of what you receive. Pro adds features such as OIDC single sign-on, LUKS data-at-rest encryption, FIPS mode, OS STIG compliance, the Security Onion API and professional support, sold on 1 to 5 year terms. Ask the vendor which of those features and terms apply to your deployment, and whether the Pro license changes any of the ELv2 conditions for your use. Your QRadar comparison should also account for this. QRadar on premises is licensed under IBM's commercial terms, so both platforms carry license obligations, but the obligations differ in kind and in what they bind you to, and each needs its own review.
Where network and log data lives under each model
Network and log data goes wherever the platform stores it, so the deployment model decides who controls retention, access and recovery. The cards below compare QRadar appliances, the QRadar SaaS history, and Security Onion running on your own infrastructure, including air-gapped and packet capture considerations.
QRadar on-premises appliances
QRadar on premises keeps events, flows and offense data on IBM appliances or virtual servers in your data center. Storage, backup and hardware refresh sit with your team, and IBM supplies features and support for this model. Before comparing, confirm where your flow and event data is stored, how long it is retained by default, and how fast you can restore it after an appliance failure.
QRadar SaaS history
Palo Alto Networks completed its acquisition of IBM's QRadar SaaS assets on September 4, 2024. Eligible SaaS customers were offered free migration to Cortex XSIAM, so any data that sat in the SaaS tenant now depends on that migration path or a retained export. Check whether your organization still holds SaaS data, and which contract governs its retention. The sibling page on QRadar SaaS covers the options in detail.
Security Onion on your infrastructure
Security Onion runs as a distribution on hardware or virtual machines you control, with a manager, sensor and search nodes in the recommended distributed design. Suricata, Zeek and full packet capture stay inside your network boundary, and the Console and Elasticsearch data remain on your storage. Confirm which node holds which data, and how a manager outage affects search nodes, since the architecture docs say search nodes stop indexing when they cannot reach the manager.
Air-gapped operation with ISO media
Security Onion supports full installs on networks without internet access. The ISO carries packages along with NIDS, YARA and Sigma rules, and the soup update tool applies newer ISO media in airgap mode. Your team owns the media transfer process, the rule refresh cadence and the validation of each new ISO before it reaches a restricted zone. Ask who authorizes media imports and how rule content is reviewed.
Packet capture storage sizing
Full packet capture produces far more data than logs, so storage sizing drives the hardware plan for sensors and search nodes. Security Onion 3.0.0 replaced Stenographer with Suricata for full packet capture, which changes how capture data is written and retained on each sensor. Ask your architect for a retention target in days, the traffic volume at each sensor, and the disk layout required to hold that window. Hardware minimums in the docs are a floor, not a sizing result.
Identity and compliance controls
Security Onion Pro adds OIDC single sign-on to the Console, LUKS data-at-rest encryption, FIPS mode and OS STIG compliance, which map to access and cryptography questions auditors often ask. These are features to configure and evidence, not certifications. Confirm whether your assessor requires FIPS-validated modules, how the OIDC provider handles MFA and session lifetime, and who holds the audit logs for Console access.
Choosing a Security Onion deployment type
Import and Evaluation are the deployment types for learning the platform and testing detections before committing hardware. Import is intended for reviewing existing packet captures or logs offline, while Evaluation gives a working console to explore Suricata alerts, Zeek logs and the Detections interface. Neither type should carry production traffic or be treated as the basis for capacity planning, because the data path is not sized for sustained load.
- Purpose: use these types to validate alert content, dashboards and analyst workflows against sample data.
- Data source: Import works from captures or logs you supply, which suits forensic review of a past incident.
- Capacity: do not extrapolate production sizing from a trial host, since it does not reflect sensor or search node load.
- Migration path: plan a fresh build for production rather than converting a trial host in place.
Confirm with the Security Onion documentation which deployment type matches each of your planned trial objectives before you assign hardware.
Standalone runs the manager, sensor and search functions on one node. It fits small networks, a single monitored segment or a proof of concept that needs live traffic. The minimum for a standalone node is 4 cores, 24 GB RAM, 200 GB storage and 2 NICs, and the platform supports only x86-64 processors.
- Scope: one sensor watching one or a few network segments, with search and console on the same host.
- Failure domain: a single host failure stops collection, detection and search together.
- Hardware: the 24 GB RAM and 200 GB storage floor is a starting point, and storage needs grow with retention and packet capture volume.
- Network placement: the two NICs separate monitoring traffic from management access, so plan switch mirroring or a tap before installation.
- Upgrades: a single node means one maintenance window for the whole stack.
Ask your QRadar team which event and flow sources currently feed the appliance, then confirm whether one standalone host can carry that traffic with packet capture enabled.
Distributed is the recommended design for production. It separates a manager node from one or more sensor nodes and one or more search nodes, so collection, indexing and the console can scale and fail independently. This is the model closest in spirit to a QRadar deployment with console, event processors and flow processors, although the roles do not map one to one.
- Manager node: minimum 4 cores and 16 GB RAM, it coordinates the deployment and the console.
- Sensor nodes: minimum 4 cores, 12 GB RAM and 2 NICs each, placed at network segments you need to observe.
- Search nodes: minimum 4 cores and 16 GB RAM each, scaled out as query and retention demand grows.
- Manager dependency: if the manager goes down, search nodes stop indexing because they cannot reach Redis, so the manager needs the strongest availability plan in the design.
- Receiver nodes: these add pipeline redundancy and load balancing, which reduces the impact of a single component failure.
When you compare with QRadar, ask whether your current appliances run as a console with processors or as all-in-one units, since that determines how many Security Onion roles you need to staff and maintain.
QRadar is available as hardware appliances and as software for supported hardware, and the choice affects refresh cycles, support contracts and capacity planning. Security Onion is software only, installed on hardware or virtual machines you provide, so the deployment decision becomes an infrastructure decision. Neither model is simpler in every case, and the comparison depends on the hardware you already own and the team that will run it.
- Hardware ownership: with QRadar appliances, the vendor's hardware cycle sets the refresh timing; with Security Onion you buy and replace servers on your own schedule.
- Architecture: a distributed Security Onion design requires you to size each role, while appliance sizing is often specified by the vendor.
- Installation media: Security Onion installs from ISO media, which supports air-gapped builds, so confirm your isolation requirements early.
- Platform base: Security Onion 3.0.0 supports only Oracle Linux 9, so check that your operating system standards allow it.
- Support model: Security Onion Pro adds professional support as a paid tier, while the free edition relies on community channels and your own staff.
Request a written bill of materials from your hardware vendor and cross-check each role against the minimums in the Security Onion hardware documentation before you accept a sizing.
What drives cost on each side
The main cost difference is that QRadar charges for what it ingests or how it is sized, while Security Onion charges nothing for the open distribution. On the QRadar side, the license is typically priced by events per second (EPS), by flows per minute (FPM) or by Managed Virtual Servers (MVS), depending on how your contract was written. Confirm which metric applies to your environment, and ask IBM or your reseller to show the current rate for each component, including flow licensing if you collect network flows. Recurring costs on that side include the annual support renewal and, on appliance deployments, the periodic hardware refresh. Ask for the support term, what the renewal covers and whether any appliance replacement is quoted separately from the software.
On the Security Onion side, the one-time and recurring costs sit in infrastructure and people. The distribution itself has no license fee, but a production design uses the Distributed deployment with a manager node, sensor nodes and search nodes. The published minimums are 4 cores and 16 GB RAM for a manager or search node and 4 cores, 12 GB RAM and 2 NICs for a sensor, so sensor count follows your traffic volume and the number of links you tap. Full packet capture and Suricata logs drive storage growth more than anything else, and retention length is the lever you control. Ask your team to size packet retention against the traffic you actually monitor, not against a generic estimate.
Staff time recurs on both sides and is often the largest line item. Security Onion requires your team to tune NIDS rules, suppress noisy signatures, manage Sigma rules and keep upgrades current, and the EOL dates for each release line shape when you must rebuild. Security Onion Pro is an optional paid tier sold on 1 to 5 year terms, and it adds professional support, OIDC single sign-on, FIPS mode and other controls. Compare that term against your support renewal, and for any outside implementation or support, request a written scope, a list of deliverables and the hours each part assumes.
Questions buyers ask before choosing Security Onion over QRadar
How much effort does a Distributed Security Onion deployment take?
A Distributed deployment is the recommended production design, and it takes more planning than a single node because you run a manager, one or more sensors and one or more search nodes. The Security Onion architecture documentation notes that if the manager goes down, search nodes stop indexing because they cannot reach Redis, so you need to plan for manager availability and for receiver nodes if you want pipeline redundancy and load balancing. Effort rises with the number of sensors, the network tap or span design, the storage sizing and the number of detection rules you tune. Ask your team to map sensor placement and retention before any hardware is ordered, and confirm the current minimum hardware figures in the Security Onion hardware documentation.
Can our team run Security Onion without outside help?
Yes, many teams run Security Onion in-house, but the answer depends on whether you have people who already operate Linux, Elasticsearch-style search clusters and Suricata or Zeek tuning. The platform bundles the console, detections, full packet capture and log management, so the skills gap is usually in day-two work: tuning NIDS rules, managing suppressions, reviewing Sigma detections and keeping the cluster healthy. Consider the following when you decide:
- Staff with Linux and network security operations experience to run the console and sensors
- Someone who owns detection tuning and alert triage over time
- Capacity for upgrades, which for 2.4 installations has a defined end-of-life date
If the skills are missing, DeployOpen can help plan, implement, harden, document and support the platform in your own infrastructure under a written scope or retainer.
How long does a migration from QRadar to Security Onion take?
No migration duration is supplied for this comparison, so treat any number you hear as unverified until a written plan confirms it. The time depends on the number of log sources and flow sources you need to replace, how much QRadar content (offenses, custom rules, saved searches and reports) you want to rebuild, how many network segments need sensors, and whether you run in an air-gapped network. Security Onion's ISO-based airgap installs and its Import and Evaluation deployment types can shorten early validation, but production sensor placement and tuning usually take the longest. Ask any partner to break the plan into discovery, build, parallel run and cutover phases, each with named deliverables.
Does the Elastic License 2.0 block our use case?
The Elastic License 2.0 is a source-available license, not an OSI-approved open-source license, so the Security Onion repository is not open source in the strict sense. In practice, ELv2 restricts providing the software as a hosted or managed service to third parties and removing license key protections, so an internal security operations team running Security Onion in its own infrastructure is usually a different case from offering it as a service. Your legal counsel should read the Security Onion repository and its LICENSE file against your intended use, especially if you are a managed security provider, a reseller or a company that embeds the product in a customer offering. Also note that Security Onion Pro is a separate paid tier.
What changes if we run Security Onion 2.4 and move to 3.0.0?
Security Onion 2.4 reached end of life on October 1, 2026, so existing installations need a planned upgrade or rebuild. According to the 3.0.0 release information, 3.0.0 supports only Oracle Linux 9 and replaced Stenographer with Suricata for full packet capture. A 2.4 installation on Oracle Linux 9 can upgrade to 3 after you move full packet capture from Stenographer to Suricata, while other distributions need a fresh install. Plan a test environment, export your detection tuning and custom content, and check that your analysts' saved searches and dashboards still work after the move. Review the Security Onion end-of-life documentation for current dates before you set a schedule.
Does Security Onion cover the log-based detection QRadar provides?
Security Onion is strongest at network visibility, combining Suricata, Zeek and full packet capture, and it includes Sigma rules loaded into ElastAlert for log-based detections. It does not replace every QRadar capability by itself, so you should map your offense rules, log source coverage and compliance reports before deciding. Teams that need broad endpoint and host log correlation often pair Security Onion with Wazuh for host-based detection. Ask for a gap list that marks each QRadar use case as covered, partly covered or not covered, and confirm any log source connector against the current Security Onion documentation.
What should we ask a partner for in a fixed-scope quote?
Ask for a written scope, deliverables and timeline before work starts, since most engagements are fixed-scope. The quote should list the sensors, manager and search nodes to be built, the log and flow sources in scope, the QRadar content to be assessed or rebuilt, the air-gap or internet-connected installation model, and the documentation and handover items. Ask which items are one-time work and which recurring, such as retainers for upgrades, detection tuning, continuous testing or support. DeployOpen does not publish a price list, so ask for a quote that follows from the agreed written scope, and compare each line against the same scope.
How a move from QRadar to Security Onion is sequenced
The sequence starts with an inventory of traffic sources and QRadar content, then builds and tunes Security Onion while QRadar keeps running. Detections are validated against the same traffic before QRadar is retired in stages. Events and network history usually need separate export paths, so those are planned at the start.
Inventory flow sources, packet sources and QRadar content
Your team lists every network span, tap and flow source feeding QRadar, along with the QRadar custom rules, building blocks, reports and saved searches that depend on flow data. Security Onion's sensors need mirrored or tapped traffic, so each flow source must be mapped to a sensor placement that can see the same segments. Confirm with your network team which links carry full packet data and which only carry NetFlow or IPFIX records, because Security Onion does not replace flow collectors in the same way QRadar does. The step is done when each QRadar rule is tagged as network-based, log-based or flow-based, and each sensor location has a named owner.
Size and build the Security Onion nodes
Your platform engineers choose between a Standalone node and a Distributed design, which Security Onion's architecture docs recommend for production, with a manager, one or more sensors and one or more search nodes. Hardware must be x86-64, and the hardware docs set minimum cores, memory, storage and NIC counts for each role, which you should check against the traffic volumes from the inventory. Confirm the supported Oracle Linux 9 platform and the current release line with the vendor before ordering hardware. The step closes when the nodes are installed, the manager reaches the search nodes, and the console loads with a test sensor reporting traffic.
Tune NIDS, Sigma and YARA content in Detections
Your detection engineers move the logic that matters from QRadar into the Security Onion Console Detections interface. Suricata NIDS rules can be modified, suppressed or given thresholds, Sigma rules run through ElastAlert with custom filters, and YARA rules run through Strelka. QRadar rules that depend on AQL logic or offense correlation will need to be rewritten, not copied, and some may have no direct equivalent. The step is done when each retained rule has a documented owner, a suppression or threshold rationale for each tuned NIDS rule, and a record of which QRadar rules were rebuilt, replaced or dropped.
Run Security Onion in parallel with QRadar
Your SOC feeds the same sensor traffic to Security Onion while QRadar continues to collect events and generate offenses as normal. Analysts work both consoles for the same incidents during this period, so the team can see where the two platforms disagree. Keep QRadar's licensing, support and appliance renewals in place for the whole parallel period, since they are not reduced by running a second platform. The step closes when the SOC agrees on which alerts each platform raises and where it has gaps in coverage.
Validate detections against the same traffic
Your detection engineers replay or reproduce known test activity, such as a sample attack set or internal red team traffic, and confirm that each retained rule fires in Security Onion and in QRadar when expected. Compare false positive rates and missed detections for each rule, and record the differences. Where QRadar relied on event correlation that Security Onion does not provide, add a documented compensating control, such as a Wazuh rule or a Sigma detection on log data. The step is done when every critical use case has a passing test result that is kept as evidence.
Plan separate exports for events and network history
Your team treats event history and network history as two separate migrations. QRadar event and offense data exports through its own paths, and the QRadar export guidance covers Log Activity exports, Ariel API result downloads and contentManagement.pl for rules, reports and saved searches. Full packet captures and flow records generally do not move into Security Onion in the same format, so retention and access for historical network data must be decided separately. Confirm with your records and legal owners how long each data type must be kept and where it must be stored. The step is done when each data class has a documented export path, retention period and storage location.
Retire QRadar in stages
Your platform owner removes QRadar's log sources, flow sources and rules in stages, starting with the lowest-risk network segments and keeping the appliance online until historical exports are verified. Each stage ends with a review of detection coverage and a sign-off from the SOC lead. Before the final stage, confirm the status of any QRadar support or license terms with IBM or your reseller, since this affects when renewals stop. The sequence is complete when QRadar holds only archived data, the retention commitments are met and the runbooks point to Security Onion.
When staying on QRadar still makes sense
QRadar remains the better choice when the investment in its content is larger than the cost of changing platforms. If your team has spent years building custom offenses, building blocks, rules and reports, and those detections cover your compliance obligations, moving them to a Security Onion stack means rewriting logic that already works. Before you decide, export an inventory of your rules and offenses and estimate how much of it would need a rebuild. Security Onion's detections interface manages Suricata NIDS rules, Sigma rules and YARA rules, but it does not read QRadar content, so every custom correlation logic becomes new work for your team.
The second condition is staffing. Analysts who work daily in AQL, the QRadar query language, and know the Log Activity and Network Activity views can keep investigating without retraining. Security Onion's hunting workflow is built on Suricata alerts, Zeek logs and full packet capture, and it relies on the Elastic Stack for search, so analysts need to learn a different query model and a different set of network telemetry. Your team also needs to be comfortable running a Linux distribution, with a manager, sensor and search node layout that depends on Redis connectivity between the manager and the search nodes. If nobody on staff wants to own that cluster, a platform with vendor support and packaged SIEM workflows is the safer fit.
Support is the final test. Confirm with IBM what on-premises QRadar support covers, which versions and fixes are in scope, and whether flow and network activity features are included in your license model, since those details change over time. Ask whether IBM will continue to offer the on-premises product on terms that match your renewal horizon. Security Onion's support depends on the edition you choose: the community project is free, while Security Onion Pro adds professional support and other features on paid terms, so compare that against what your organization requires. Staying on QRadar is a defensible decision when these answers come back in its favor, and it should be recorded with the same care as a migration.
How DeployOpen helps evaluate and implement Security Onion
DeployOpen plans, implements, hardens, documents and supports self-hosted open-source platforms inside your own cloud accounts, data centers or air-gapped networks. For IBM QRadar vs Security Onion, we start with a written scope covering your sensor placement, traffic volumes and retention needs before any build begins.
How we scope
- Map which QRadar flow and event sources need Security Onion sensor coverage and which stay in a log platform
- Size manager, sensor and search node counts against your traffic and retention targets, not assumed figures
- Confirm air-gapped, internet-connected or hybrid operation and the update path for rules and packages
- Agree in writing the deliverables, timelines and Elastic License 2.0 review points before work starts
How we build
- Deploy Security Onion in a distributed layout with manager, sensor and search nodes in your environment
- Tune Suricata and Zeek rules and Sigma detections through the Console Detections interface
- Test detections against captured traffic and document which QRadar offenses have equivalents
- Integrate authentication, log forwarding and alert routing into the systems your team already runs
How we hand over
- Deliver configuration, architecture diagrams, runbooks and detection inventories as written documentation
- Walk your operations and security staff through daily triage, rule changes and node maintenance
- Record the open items, such as features not covered by the community edition, for your own decision
- Prepare system and control evidence for your compliance assessors, who issue any audit report or certification
How we support
- Ongoing support, upgrades and continuous testing are available as retainers after handover
- Plan upgrades against Security Onion end-of-life dates and the move from Stenographer to Suricata capture
- Re-run security testing of the deployment when sensors, nodes or detection content change
- Ask any provider, including us, to confirm current release, license and support terms in writing before you buy
