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Cybersecurity · head to head

IBM QRadar vs Tenable 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
Tenable Nessus logo

Tenable Nessus

Cybersecurity

Network vulnerability scanner

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only Tenable Nessus has a free tier, so it costs nothing to try first.
  • 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.; 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: IBM QRadar covers Offence model, Tenable Nessus covers Network scanning.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

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

Attributes where IBM QRadar and Tenable Nessus differ
AttributeIBM QRadarTenable Nessus
Starting priceOn requestFree
Free tierNoYes
PlatformsWeb, ApiWindows, Linux, Macos, Cloud
Founded19112002

Identical on both: pricing model (subscription), 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 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.

IBM QRadar

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

Tenable Nessus

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

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

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

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 IBM QRadar if

  • You need offence model.
  • You work on Web, Api.
  • You also want network flow analysis.
IBM QRadar 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 IBM QRadar or Tenable Nessus better?
Neither clearly leads. IBM QRadar starts at On request and Tenable Nessus at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, IBM QRadar or Tenable Nessus?
Tenable Nessus has a free tier; the other does not. Paid plans start at On request for IBM QRadar and Free for Tenable Nessus.
Does IBM QRadar or Tenable Nessus run on more platforms?
IBM QRadar runs on Web, Api. Tenable Nessus runs on Windows, Linux, Macos, Cloud.
Can I use Tenable Nessus for free?
Yes. Tenable Nessus has a free tier, so you can try it without paying. IBM QRadar starts at On request.
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 Tenable Nessus is typically brought in for.
What can IBM QRadar do that Tenable Nessus cannot?
IBM QRadar covers Offence model, Network flow analysis, Device Support Modules, Ariel query language. Tenable Nessus covers Network scanning, Vulnerability detection, Configuration assessment, Malware detection.

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.

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
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.

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
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.

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
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.

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
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.

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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