Tenable Nessus and Qualys VMDR are mature enterprise-grade vulnerability assessment platforms that scan networks and endpoints for known CVE-rated vulnerabilities. Sherlock EoP Auditor is a Windows endpoint surface scanner that tests for local privilege escalation paths that often have no CVE assigned. The three tools cover different facets of Windows security. Nessus and VMDR cover the CVE-class layer for fleet visibility. EoP Auditor covers the configuration-class privilege escalation layer for individual host hardening. The honest practitioner posture is to run a CVE-class scanner across the fleet plus run EoP Auditor on demand against high-value hosts.
What Tenable Nessus tests
Tenable Nessus is the most widely deployed network vulnerability scanner in mid-market security programs. The tool scans networks plus authenticated endpoints against an extensive plugin library covering Windows OS vulnerabilities, third-party software CVEs, configuration baselines plus compliance frameworks. Nessus supports authenticated scanning with credentialed access to Windows hosts for deeper visibility than network-only scanning provides.
Specific findings Nessus surfaces include missing Windows patches by KB article, third-party software missing patches, exposed network services with version fingerprinting, weak SSL or TLS configurations, default credentials on common services, security baseline deviations (CIS, DISA STIG), web application surface vulnerabilities plus database server misconfigurations. The plugin library updates daily so newly disclosed CVEs typically have detection coverage within hours to days.
The reports show per-CVE severity (CVSS scores), exploitability metrics, asset inventory with finding density plus remediation priority. The Nessus Manager tier supports continuous scanning, scheduled scans plus integration with patch management platforms. Cost scales with the number of IPs being scanned.
What Qualys VMDR tests
Qualys VMDR (Vulnerability Management Detection Response) is a cloud-native vulnerability management platform that combines asset discovery, vulnerability scanning, threat prioritization plus integrated patch deployment in a single pane of glass. The platform deploys lightweight agents on endpoints (Cloud Agent) plus uses network scanners for unagented assets.
Specific findings VMDR surfaces include missing Windows patches by KB article, third-party software CVE inventory, exposed network surface, security baseline compliance, asset inventory drift detection, certificate inventory plus the proprietary Threat Adjusted Risk Score (TruRisk) that prioritizes vulnerabilities by real-world exploitation likelihood not just CVSS.
The reports surface per-vulnerability detail with proprietary risk scoring, integrated patch deployment workflow, fleet-wide compliance posture plus executive-summary dashboards suitable for board reporting. The continuous Cloud Agent collection plus the integrated patch workflow are the differentiators against Nessus. Cost scales with asset count plus feature tier.
What Sherlock EoP Auditor tests
Sherlock EoP Auditor is a Windows endpoint surface scanner that enumerates local privilege escalation conditions. The tool runs on demand against a single host. The use case is point-in-time forensic audit of the local Windows attack surface, not continuous fleet monitoring.
Specific findings EoP Auditor surfaces include third-party Windows services running as SYSTEM with authorization gaps, kernel driver attack surfaces, named pipe authorization issues in privileged services, scheduled task misconfigurations, COM object permission gaps, registry key ACL issues plus file system permission vectors on privileged executables. The findings often have no CVE assigned because they are configuration-class issues plus design-class issues in third-party software.
The tool surfaces what a human penetration tester would find during a local privilege escalation audit on a Windows host. The difference is automation: the tool runs in seconds where the human audit takes hours plus the output is reproducible.
Coverage matrix
CVE-class Windows OS vulnerabilities: Nessus covers comprehensively. VMDR covers comprehensively. EoP Auditor does not patch-scan.
CVE-class third-party software vulnerabilities: Nessus covers via plugin library. VMDR covers via Cloud Agent inventory. EoP Auditor does not.
Network surface enumeration: Nessus covers extensively. VMDR covers via scanner appliances. EoP Auditor does not (it is host-local only).
Security baseline compliance (CIS, DISA STIG): Nessus covers via dedicated compliance scans. VMDR covers via Policy Compliance module. EoP Auditor does not test compliance benchmarks.
Continuous fleet monitoring: Nessus Manager supports scheduled scans. VMDR Cloud Agent supports continuous. EoP Auditor runs on demand only.
Third-party Windows service authorization gaps: EoP Auditor covers in depth. Nessus partial coverage via plugin library if specific service has CVE. VMDR partial coverage same way. The configuration-class findings without CVE assignment are EoP Auditor exclusive.
Named pipe authorization gaps: EoP Auditor covers. Nessus does not (no scanner plugin exists for arbitrary third-party named pipes). VMDR does not.
Kernel driver attack surfaces: EoP Auditor covers. Nessus partial via outdated-driver flagging. VMDR similar partial coverage.
COM object permission gaps: EoP Auditor covers. Nessus does not. VMDR does not.
Integrated patch deployment workflow: VMDR covers natively. Nessus integrates with external patch management. EoP Auditor does not deploy patches; it surfaces configuration findings.
Asset inventory plus discovery: Both Nessus and VMDR cover. EoP Auditor scans only the host it runs on.
Where Nessus vs VMDR differ
Nessus and VMDR overlap substantially on CVE-class findings. The differentiators are operational, not technical.
Nessus is deployed on-premises (Nessus Professional) or in a self-hosted cloud (Nessus Manager) with the customer owning the platform. VMDR is cloud-native with Qualys hosting the platform plus the customer deploying agents only. The choice between them often comes down to data residency requirements plus operational preference for owning the platform vs consuming it as a service.
VMDR has stronger integrated patch deployment workflow. Nessus has a more extensive plugin library plus broader third-party software CVE coverage. VMDR's TruRisk scoring is a real differentiator for prioritization (CVSS alone often misleads about real-world exploitation likelihood). Both vendors are credible mid-market choices.
Cost and operational characteristics
Tenable Nessus annualized cost for a mid-market organization typically runs five figures USD depending on IP count plus feature tier (Nessus Professional vs Nessus Manager vs Tenable.io). Qualys VMDR pricing is comparable in the same range, scaling with asset count plus feature module selection.
Sherlock EoP Auditor is a one-time per-license tool that runs on demand against individual Windows hosts. The cost structure is materially below the SaaS vulnerability management tier because the use case is different (targeted host audit, not continuous fleet monitoring). The two cost classes are not substitutes for each other.
The operational pattern that mature security teams adopt is to deploy Nessus or VMDR for continuous CVE-class fleet visibility plus run EoP Auditor on demand against specific hosts that warrant deeper privilege escalation surface audit. New Windows server deployments, post-incident host audits plus pre-production validation of new third-party Windows software are the primary EoP Auditor use cases.
When each tool is the right starting point
Choose Tenable Nessus first if the question your security program needs to answer is "are our Windows endpoints fully patched against known CVEs plus aligned with security baselines?" Nessus is the right starting choice if you want to own the platform on-premises, want the broadest plugin library plus already have or are willing to invest in patch management workflow integration.
Choose Qualys VMDR first if the same question matters but you prefer a cloud-native platform with integrated patch deployment workflow plus the TruRisk scoring for real-world prioritization. VMDR is the right starting choice if you want fewer moving parts in your VM stack plus value the integrated dashboard.
Choose Sherlock EoP Auditor as a complement if the question your security program also needs to answer is "do our Windows endpoints have local privilege escalation surfaces that patches will not fix?" EoP Auditor is the right complement to either Nessus or VMDR because it covers a non-overlapping attack surface. Running CVE-class scanning without privilege escalation auditing leaves the configuration-class findings entirely unaddressed.
What this means for security planning
The mistake security programs make is treating CVE-class vulnerability management as complete Windows hardening. It is not, regardless of which CVE-class scanner you pick. The Sherlock Forensics incident response casework consistently surfaces breaches where the compromised host was fully patched per the chosen CVE scanner plus contained configuration-class escalation surfaces that the attacker leveraged. The host passed every Nessus or VMDR scan plus still got compromised because the underlying authorization gap was never represented as a CVE.
The honest practitioner posture is to layer both classes of scanner. Pick a CVE-class platform that fits your operational preference (Nessus for on-premises, VMDR for cloud-native) plus add configuration-class privilege escalation testing via EoP Auditor on the hosts that matter most.
The Sherlock Forensics services practice handles ransomware response, breach investigation plus court-defensible forensic examination. The forensic toolchain includes the Sherlock Disk Imager for acquisition with chain of custody, the Sherlock Universal Events Viewer for timeline reconstruction plus the Sherlock EoP Auditor for privilege escalation surface assessment. Talk to our team about incident response or proactive Windows hardening assessment.
CVE-class scanning and configuration-class auditing are different security disciplines. Get on the EoP Auditor early access list for the configuration-class privilege escalation layer. Talk to our team about integrating it with Nessus or VMDR in your Windows hardening program.