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Cybersecurity · head to head

IBM QRadar vs Nessus

IBM QRadar logo

IBM QRadar

Cybersecurity

Enterprise SIEM licensed by events per second, whose cloud business IBM sold to Palo Alto Networks in 2024.

From
On request
Rated
-
Full reviewWebsite
Nessus logo

Nessus

Cybersecurity

The most trusted vulnerability assessment solution

From
$4790/year
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: IBM QRadar iBM sold the QRadar SaaS business to Palo Alto Networks in 2024 and those customers are being moved to Cortex XSIAM, so anyone buying today is choosing an on-premises product whose vendor has publicly moved the cloud future to a competitor, and the support horizon becomes a contract negotiation rather than an assumption.; Nessus nessus Professional is $4,790 for one year, with no free or low cost commercial tier
  • They diverge on capability: IBM QRadar covers Offence model, Nessus covers Vulnerability scanning.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which IBM QRadar and Nessus actually diverge.

Attributes where IBM QRadar and Nessus differ
AttributeIBM QRadarNessus
Starting priceOn request$4790/year
PlatformsWeb, ApiDesktop, Api
Founded19112002

Identical on both: pricing model (subscription), free tier (No), 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 IBM QRadar

  • Offence model
  • Network flow analysis
  • Device Support Modules
  • Ariel query language
  • Rules and building blocks
  • Deployment topology
  • App Exchange
  • Use Case Manager

Only in Nessus

  • Vulnerability scanning
  • Configuration auditing
  • Malware detection
  • Web application scanning
  • Cloud scanning
  • Compliance checks
  • Patch auditing
  • Pre-built policies

What people use each for

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

IBM QRadar

  • A regulated enterprise that must keep log data on premises or in a specific jurisdiction and cannot use a shared SaaS SIEMnot Nessus
  • A SOC that wants log correlation and network flow analysis in one platform rather than buying an NDR product separatelynot Nessus
  • An existing QRadar estate deciding whether to stay on premises or accept the migration path to a different vendor's platformnot Nessus
  • Compliance-driven log retention and reporting where the audit requirement is specific about collection, retention and reportingnot Nessus

Nessus

  • Vulnerability scanning for individual practitionersnot IBM QRadar
  • Enterprise vulnerability managementnot IBM QRadar
  • Web application security assessmentsnot IBM QRadar

Where each one falls short

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

IBM QRadar

  • IBM sold the QRadar SaaS business to Palo Alto Networks in 2024 and those customers are being moved to Cortex XSIAM, so anyone buying today is choosing an on-premises product whose vendor has publicly moved the cloud future to a competitor, and the support horizon becomes a contract negotiation rather than an assumption.
  • Licensing is by events per second and flows per minute, so every additional log source raises the cost directly and teams routinely exclude verbose sources such as DNS, proxy, endpoint and cloud audit logs to stay under the licence, which strips out exactly the data an investigation later needs.
  • It needs a dedicated operator: rule tuning, parser work and offence triage are continuous jobs, and an organisation that deploys QRadar without at least one named engineer accumulates thousands of unreviewed offences and a false sense of coverage.
  • A log source without a matching Device Support Module arrives unparsed, and writing a custom parser with regular expressions against an unfamiliar payload format is specialist work that can take days per source, which quietly determines which systems ever get monitored.
  • On-premises capacity is planned across consoles, processors, collectors and data nodes, so outgrowing the sizing means procuring and racking more appliances rather than changing a subscription tier, and growth becomes a purchasing cycle measured in months.

Nessus

  • Nessus Professional is $4,790 for one year, with no free or low cost commercial tier
  • Multi year terms are the only discount route, at $9,330.95 for two years and $13,637.54 for three
  • It is a single user scanner, so team workflows mean migrating to another Tenable product
  • Tenable One vulnerability management is priced separately, starting at $3,500 a year for 100 assets

Pricing, plan by plan

IBM QRadar

On request
  • QRadar SIEMFree
    • Event and flow processing
    • Offense management
    • Threat intelligence
  • QRadar CloudFree
    • Cloud-native deployment
    • Elastic scaling
    • Managed infrastructure
  • QRadar SuiteFree
    • SIEM + SOAR + XDR
    • Unified analyst experience
    • Federated search

Nessus

$4790/year
  • Nessus Professional$4790/year
    • 1 year license
    • Best for individual security professionals
  • Nessus Professional 2-Year$9330.95/2 years
    • 2 year license with discounted rate vs. annual
  • Nessus Professional 3-Year$13637.54/3 years
    • 3 year license with discounted rate vs. annual
  • Nessus Expert$6790/year
    • 1 year license
    • Enhanced capabilities vs. Professional

Which should you pick?

Choose IBM QRadar if

  • You need offence model.
  • You work on Web, Api.
  • You also want network flow analysis.
IBM QRadar review

Choose Nessus if

  • You need vulnerability scanning.
  • You work on Desktop, Api.
  • You also want configuration auditing.
Nessus review

Questions people ask

Is IBM QRadar or Nessus better?
Neither clearly leads. IBM QRadar starts at On request and Nessus at $4790/year, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, IBM QRadar or Nessus?
IBM QRadar starts at On request and Nessus at $4790/year.
Does IBM QRadar or Nessus run on more platforms?
IBM QRadar runs on Web, Api. Nessus runs on Desktop, Api.
What is IBM QRadar best used for?
IBM QRadar is most often used for a regulated enterprise that must keep log data on premises or in a specific jurisdiction and cannot use a shared saas siem, a soc that wants log correlation and network flow analysis in one platform rather than buying an ndr product separately, an existing qradar estate deciding whether to stay on premises or accept the migration path to a different vendor's platform, compliance-driven log retention and reporting where the audit requirement is specific about collection, retention and reporting. Of those, a regulated enterprise that must keep log data on premises or in a specific jurisdiction and cannot use a shared saas siem and a soc that wants log correlation and network flow analysis in one platform rather than buying an ndr product separately are not what Nessus is typically brought in for.
What can IBM QRadar do that Nessus cannot?
IBM QRadar covers Offence model, Network flow analysis, Device Support Modules, Ariel query language. Nessus covers Vulnerability scanning, Configuration auditing, Malware detection, Web application scanning.

Answered from the vendors’ own pages

IBM QRadar: Who owns QRadar now?

It is split. IBM sold the QRadar SaaS assets to Palo Alto Networks in a deal announced in May 2024 and closed that September, and those customers are being migrated to Cortex XSIAM. IBM retains and supports the on-premises product.

Nessus: What is the cheapest Nessus option?

Nessus Professional starts at $4,790 per year for a 1-year license. Multi-year commitments offer discounts, with 2-year licenses at $9,330.95 and 3-year licenses at $13,637.54.

Source
IBM QRadar: Is QRadar being discontinued?

IBM has committed to continuing support for on-premises customers, including security updates, while offering migration assistance. The cloud product's future belongs to Palo Alto. If you are signing a multi-year term, get the support horizon written into the contract.

Nessus: What is the difference between Nessus Professional and Expert?

Nessus Expert costs $6,790 per year for a 1-year license (compared to $4,790 for Professional) and includes enhanced capabilities. Multi-year rates are available at discounted prices.

Source
IBM QRadar: How is it licensed?

By events per second for logs and flows per minute for network data, with the software or appliance sized to that rate. Add-on modules in the suite are licensed separately.

Nessus: Does Nessus offer optional support or training?

Yes, Nessus offers add-on services: Advanced Support at $400/year provides 24x365 access to phone, email, community, and chat support. On-Demand Training costs $275/year for Fundamentals course access or $385/year for both Fundamentals and Advanced courses.

Source
IBM QRadar: What is an offence?

QRadar's term for a correlated case. Rules group related events and flows against a common indicator such as a host or user, so an analyst reviews one offence rather than the hundreds of events behind it.

IBM QRadar: Do I need a full-time engineer?

In practice yes for anything beyond a small deployment. Parser development, rule tuning and offence triage do not stop, and the most common failure mode is a well-installed QRadar that nobody has tuned since go-live.

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