Table of contents
- Key Takeaways
- What Are Vulnerability Scanning Tools?
- Key Features of Vulnerability Scanning Tools
- Types of Vulnerability Scanning Tools
- Top 10 Vulnerability Scanning Tools
- Benefits of Vulnerability Scanning
- Open Source Vulnerability Scanning Tools
- Choosing the Right Vulnerability Scanner
- How Orca Scans Cloud Estates Without Agents
- Frequently Asked Questions about Vulnerability Scanning Tools
Key Takeaways
- A vulnerability scanner is a detection engine, not a program. It finds flaws in a specific class of asset and hands the result to whatever system tracks the fix.
- Scanning coverage is decided per asset type, not per vendor. No tool in this comparison covers networks, web applications, source code, container images, and cloud configuration at equal depth.
- Access level changes the answer more than product choice does. An unauthenticated scan reads what a service advertises, while an authenticated scan reads what is actually installed.
- The top 10 focuses on products with dedicated vulnerability scanning capabilities, while broader management and exposure platforms are excluded from the comparison.
- Orca reads the workload’s runtime block storage out of band, which returns installed package data across a cloud estate without host credentials, agents, or network access to each machine.
Vulnerability scanning tools inspect specific asset types for known security weaknesses and report the findings to whatever system manages remediation. They are not interchangeable with vulnerability management platforms, which organize, prioritize, and track the work that follows.
Every scanner is built around a target class and an access method. A tool that authenticates to a Linux host and inventories installed packages cannot inspect a container image sitting in a registry, and neither one crawls a single-page web application.
This guide compares ten scanners by what they actually inspect. It covers the features that separate detection engines, the five major scanner types, the open-source options worth considering, and how to match a scanner to the assets in your environment.
What Are Vulnerability Scanning Tools?
Vulnerability scanning tools automate the search for known weaknesses in a defined set of targets. They apply detection logic to hosts, applications, images, or code and report each match with an identifier, location, and supporting evidence. NIST groups vulnerability scanning under technical security testing in SP 800-115, alongside network discovery and penetration testing as separate techniques with different costs and blind spots.
The output is a list of candidate findings, not a verdict. Every scanner produces some results that do not apply to the environment, which is why validation remains part of a vulnerability assessment. What separates a strong scanner from a noisy one is the evidence it collects before asserting that a weakness is present.
Scanners Versus Vulnerability Management Platforms
A scanner answers one question: is this flaw present on this asset. A vulnerability management platform answers a different set of questions about ownership, sequencing, and proof of closure. It usually consumes scanner output instead of producing it, so if you are choosing the system that will run your program, the comparison you want is of vulnerability management tools.
The practical consequence is coverage. No scanner covers every asset type equally well, and platforms differ widely in the depth of their support for hosts, containers, source code, web applications, and cloud configuration. The only reliable way to judge coverage is to compare exactly which asset types a product scans natively, how it collects the data, and whether additional components or licenses are required.
Key Features of Vulnerability Scanning Tools
Judge a scanner on what it can observe and how reliably it interprets what it sees. Feature lists across this market are close to identical, so the questions below are the ones that produce different answers from different vendors.
- Authentication modes. Credentialed scanning changes the result more than any other setting. Without credentials a scanner infers versions from banners, response headers, and open ports; with them it reads the package database directly.
- Scan target coverage. Ask which asset classes the engine parses natively: operating system packages, language dependencies, container image layers, web application responses, infrastructure as code templates, and cloud provider configuration.
- Detection content and its freshness. A scanner is only as current as its signature feed. Tenable reports more than 319,000 Nessus plugins, coverage of over 117,000 CVEs, and more than 100 new plugins released weekly, while Greenbone’s enterprise feed carries over 100,000 vulnerability tests.
- Identifier hygiene. Findings should map to CVE records and the National Vulnerability Database, with the affected product expressed in a standard form. NIST maintains that plumbing as the Security Content Automation Protocol, whose current final release is SCAP 1.4. Its components include OVAL for expressing a check and CPE for naming the affected platform.
- Accuracy and evidence. Every scanner produces some findings that do not hold up. What differs is whether the finding ships with the evidence that produced it, so an engineer can confirm or dismiss it without rerunning the scan.
- Scheduling and throttling. Automated vulnerability scanning tools run on a trigger rather than a calendar: a new image push, a deploy, a new asset appearing in an account. Rate limits and scan windows matter for anything that touches production over the network.
- Output format. JSON, SARIF, and SBOM formats decide whether findings reach a pipeline gate and a ticket queue without a human copying them.
Types of Vulnerability Scanning Tools
Scanners are grouped by what they point at, and the five types below barely overlap. Reading the same CVE from two of them can produce two different verdicts, because each one sees a different layer of the same system.
Network Vulnerability Scanners
Network vulnerability scanning tools reach a host over the network, enumerate listening services, fingerprint each one, and test it against a signature set. This is the oldest scanner type and still the default for on-premises estates, physical appliances, and anything with an IP address that no agent will ever run on. Credentialed checks turn the same tool into a host scanner that reads installed packages instead of guessing from banners.
The cloud is where this model strains. A scanner needs a route to the target and an open port to talk to, and autoscaled workloads often have neither for long. A subnet scan run at nine in the morning describes a fleet that no longer exists at noon.
Web Application Scanners
Web application vulnerability scanning tools work from the outside in. The scanner crawls an application, builds a map of its endpoints and parameters, then sends crafted requests and reads the responses for signs of injection, broken access control, or unsafe redirects. This is dynamic application security testing, and it exercises the running system, so it reaches flaws that source code alone does not reveal.
Two things limit it. Crawling a JavaScript-heavy interface is genuinely hard, and an unauthenticated crawl only reaches the login page. Application vulnerability scanning tools that cover APIs solve part of this. They take an OpenAPI specification as input instead of discovering routes by crawling, which is worth asking about when most of your surface is machine-facing.
Source Code and Dependency Scanners
Code vulnerability scanning tools read the repository. Static analysis parses your own code and flags dangerous patterns, while software composition analysis resolves the dependency tree and matches each package version against known advisories. The two answer different questions, and the split between static analysis and composition analysis is worth understanding before you buy either.
Their advantage is timing, since a finding at commit costs less than the same finding in production. Their limitation is that neither knows what shipped. A vulnerable dependency that is present in the lockfile but never loaded at runtime looks identical to one on the critical path.
Container and Image Scanners
Container vulnerability scanning tools open an image layer by layer, build an inventory of operating system packages and language dependencies, and match that inventory against advisory data. Most also scan registries on push and run as a pipeline step, which is why they are the easiest scanner type to automate. The practice around them is broader than the tooling, and container security covers the runtime half this class does not.
The failure mode is drift. A registry scan describes the image as it was built. A container that installs packages at start-up, mounts configuration, or runs a re-pushed tag no longer matches its own scan record. Scanning the registry and never scanning what runs leaves a gap that widens with every deploy, so coverage here means both.
Cloud Configuration and Infrastructure Scanners
The fifth type reads configuration instead of software. Infrastructure as code scanning checks Terraform, CloudFormation, and Kubernetes manifests before they apply, and cloud posture scanning reads the deployed state through provider APIs. Neither looks for a CVE. They look for a setting that exposes something, which makes them the only type here that finds a problem in an asset running no vulnerable software at all.
Top 10 Vulnerability Scanning Tools
This comparison focuses on products with dedicated vulnerability scanning capabilities. Broader exposure management and vulnerability management platforms whose primary value lies in aggregating, prioritizing, and managing findings rather than comparing standalone scanning approaches were excluded. The tools below are compared on their scanning capabilities, not on market share or brand recognition.
That excludes products such as Wiz (now part of Google Cloud), CrowdStrike Falcon Exposure Management, Microsoft Defender Vulnerability Management, and Palo Alto Cortex Cloud (formerly Prisma Cloud). Where vendors offer both a broader platform and dedicated scanning capabilities, this comparison focuses on the scanning technology rather than the wider management platform.
| Tool | Primary Scan Target | Deployment | Open Source | Best For |
|---|---|---|---|---|
| Orca Security | Cloud workloads, containers, and configuration | Cloud-native, agentless | No | Cloud-wide agentless scanning with no host credentials or agents |
| Tenable Nessus | Hosts and network services | Installed scanner | No | Deep credentialed host and network checks |
| Qualys | Hosts, networks, and cloud assets | Agent, appliance, or passive sensor | No | Mixed estates that need several sensor types |
| OpenVAS | Hosts and network services | Self-hosted or appliance | Yes | Network scanning with no per-target license |
| Nuclei | Web services, APIs, DNS, and network protocols | Command line | Yes | Rapid validation of specific vulnerabilities across many targets |
| Trivy | Images, filesystems, repositories, and Kubernetes | Command line or CI job | Yes | Build-time scanning inside a pipeline |
| ZAP | Web applications and APIs | Desktop, container, or CI | Yes | Open-source DAST for manual and CI testing |
| Burp Suite | Web applications and APIs | Desktop or server | No | Depth on complex, stateful web applications |
| Grype | Images, filesystems, and SBOMs | Command line | Yes | Matching an existing SBOM against advisories |
| Semgrep | Source code and dependencies | Command line, CI, or SaaS | Partial | Custom code analysis with developer-defined rules |
Orca Security: Agentless Scanning Across the Cloud Estate
Orca Security scans cloud workloads without installing anything on them. Its patented SideScanning™ technology collects data from the workload’s runtime block storage out of band, then reconstructs the file system in a virtual read-only view. The result is the kind of inventory a credentialed scan produces: operating system packages, applications, libraries, and versions. Orca gathers it through a cloud account connection, not through host credentials, agents, or a network route to each machine.
Coverage extends across virtual machines, containers and images, and serverless functions, with configuration read from the cloud provider alongside the workload data. The scope is the trade-off. This is a scanner for cloud and AI estates, so risk sitting on employee laptops or in a physical data center still needs something pointed at it.
Tenable Nessus
Nessus is the host and network scanner most practitioners learned on. It is still sold separately, in Nessus Professional and Nessus Expert editions, and remains distinct from the Tenable One platform it also feeds. Its strength is the plugin library and the depth of its credentialed checks, which include configuration and compliance audits alongside vulnerability detection.
It scans and reports, and that is the boundary. Nessus does not run the program around the finding, and pointing it at ephemeral cloud infrastructure hits the same routing and lifetime problems every network scanner faces.
Qualys
Qualys is worth evaluating for its sensor mix more than its engine. The same detection content reaches assets through scanner appliances, Cloud Agents, and a network passive sensor. That last one identifies hosts by watching traffic without any active probing, which is how you get coverage of devices that must never be scanned directly.
The flexibility is also the cost. Deciding which sensor covers which segment is real design work, and the scanning capability arrives inside a far larger platform than a team wanting only a scanner needs.
OpenVAS
OpenVAS is the long-running open-source network scanner maintained by Greenbone, and its naming changed in July 2025. Greenbone now brings its commercial products together under the OPENVAS brand, with OPENVAS COMMUNITY EDITION as the free self-hosted path and the OPENVAS ENTERPRISE FEED carrying over 100,000 vulnerability tests. The company name stays; anything written before that rebrand uses the older Greenbone product names.
The community edition’s main trade-off is that it lags the enterprise feed, and self-hosting means you own upgrades, tuning, and maintenance.
Nuclei
Nuclei inverts the usual model. Instead of a monolithic signature set, it runs community-maintained YAML templates that each describe one check, across HTTP, DNS, TCP, SSL, and other protocols. When a critical CVE lands, one template turns it into a check you can run across every host you own. Orca has published a walkthrough of Nuclei templates for vulnerability scanning that covers the mechanics.
It finds precisely what a template covers and nothing else. Nuclei is a targeted instrument, not a replacement for a general host scanner.
Trivy
Trivy began as a container image scanner and its scope has grown well past images. Aqua Security describes it as finding vulnerabilities and misconfigurations across code repositories, binary artifacts, container images, and Kubernetes clusters, and it emits SBOMs as well as findings. It installs as a single binary, runs in a pipeline step, and is licensed under Apache 2.0.
Its focus is build-time artifacts rather than runtime state. Trivy tells you what is in the artifact, and a container that has drifted from the image it started as needs something watching the running workload.
ZAP
ZAP is the open-source entry in the web application category, and its stewardship has changed. The project long known as OWASP ZAP is now ZAP by Checkmarx, remaining free and open source under the direction of the ZAP Core Team, with development supported by Checkmarx. It works as both an intercepting proxy and an automated scanner, making it suitable for manual testing as well as unattended CI pipelines.
Getting good results takes configuration. Authentication handling and coverage of dynamic front ends are where first attempts often fall short, and an unconfigured ZAP scan reports far less than the application actually exposes.
Burp Suite
Burp is the commercial counterpart, and its editions were renamed in 2025. PortSwigger sells Burp Suite Professional for individual testers, and release 2025.5 renamed Burp Suite Enterprise Edition to Burp Suite DAST for scheduled scanning at scale. Burp Scanner is the reason it appears here, since its crawl-and-audit engine handles stateful applications unusually well.
Professional is built around one tester at one desk. Scaling it across an application portfolio means the DAST edition, at an appreciable difference in price.
Grype
Grype takes an image, a filesystem, or an existing SBOM and matches its package inventory against vulnerability data. It covers the major operating system package ecosystems along with Ruby, Java, JavaScript, Python, .NET, Go, PHP, and Rust dependencies. It also pairs with Syft, which generates the SBOM that Grype then consumes.
That is deliberately all it does. Grype performs no crawling, no configuration checking, and no active probing, which makes it fast, predictable, and easy to wire into a supply chain workflow.
Semgrep
Semgrep is the code scanner on this list, and its distinguishing feature is that rules look like the code they match. That lets a team write a rule for an internal API misuse, which is where generic static analysis usually has nothing to offer. Semgrep Community Edition is the open-source engine, and the commercial tier adds cross-file, cross-function dataflow analysis on top of it.
The split between those two matters more than it looks. Semgrep’s own documentation warns that the Community Edition “can only analyze code within the boundaries of a single function or file,” so it will miss real issues that cross those lines. Rules-based analysis also requires source access, does not observe runtime behavior, and its coverage varies by language and by the maturity of the available rules.
Benefits of Vulnerability Scanning
The first benefit is arithmetic. Manual review does not scale past a few dozen hosts, and scanning turns an unbounded inspection task into a scheduled job whose output is a list. Everything downstream, from patching to audit evidence, depends on that list existing.
The second is that scanning creates a record over time. A finding that appears, disappears, and reappears tells you something a point-in-time review cannot: a fix is not holding, or a base image regressed. Scan output is also the raw material for risk prioritization and risk-based vulnerability management, where a CVSS score meets exposure and reachability to produce an order of work. Those are program activities, and they need a scanner underneath them to have anything to sort.
Open Source Vulnerability Scanning Tools
The open source vulnerability scanning tools worth running are mostly already named above. OpenVAS covers networks and hosts, Nuclei handles targeted checks, Trivy reads images and infrastructure code, ZAP scans web applications, and Grype matches packages from an SBOM. Syft belongs alongside Grype as the inventory step, and OSV-Scanner is worth a look for dependency data drawn from the OSV database.
Two more sit at the edges of this category. Semgrep’s engine is open source with commercial analysis layered on top. DefectDojo, an OWASP flagship project, is not a scanner at all but the aggregation layer teams reach for once they run several. The wider question of which free tooling to assemble across an application program is covered in open source application security tools.
The shared cost is operational. You host it, you update it, you tune it, and you reconcile findings across tools yourself.
Choosing the Right Vulnerability Scanner
Match the Scanner to the Asset Type
Start by listing what you run, then check which target class each item falls into. Network-reachable hosts, web applications and APIs, source repositories, container images, and cloud configuration are five separate problems, and a tool strong in one is usually thin in the next.
The gap is what you are shopping for. When a network or host scanner is already in place, the shortfall usually sits in containers, code, or configuration. That makes a second general-purpose scanner the least valuable thing to buy. Deciding which system should run the program around these tools is a separate, platform-level question.
Authenticated Versus Unauthenticated Scanning
Access level changes the finding. An unauthenticated scan reads a service banner announcing OpenSSH 8.9 and reports every CVE affecting that version. An authenticated scan reads the installed package, sees that the distribution backported the fix into its own build, and drops most of those results as a false positive. Same tool, same host, two different answers.
The reverse error costs more. A scanner given no credentials for a database host cannot log in, so it reports almost nothing and the host looks clean. Before accepting a clean result, confirm the scanner had a way in, and treat any target where authentication silently failed as unscanned rather than unaffected.
How Orca Scans Cloud Estates Without Agents
Traditional scanners depend on network access, host credentials, or agents installed on every workload. Orca takes a different approach. Its patented SideScanning™ technology reads workload runtime block storage out of band through the cloud provider’s virtualization layer, giving it the visibility of a credentialed scan without per-host credentials, agents, or network access.
Orca builds an inventory of operating system packages, applications, libraries, and versions across virtual machines, containers, and serverless functions, drawing on more than twenty vulnerability data sources. Findings are correlated in the Unified Data Model, where Agentless Reachability Analysis identifies vulnerable packages that are potentially executable at runtime, helping teams prioritize the findings most likely to matter. For workloads that require execution telemetry, the optional Orca Sensor provides that additional signal. Get a demo to see how Orca scans your cloud estate.
Frequently Asked Questions about Vulnerability Scanning Tools
Tie the cadence to change, not to the calendar. Pipeline scanners should run on every build and every image push. Cloud configuration needs continuous evaluation because it changes without a deployment. Network scans against stable infrastructure fit a weekly rhythm, with an out-of-band run whenever a major CVE is published.
No. Vulnerability scanning automates checks for known weaknesses across defined targets. Penetration testing uses human-led analysis, often supported by automated tools, to determine whether weaknesses can be exploited or combined into meaningful attack paths. NIST SP 800-115 treats them as separate techniques with different costs and blind spots. The two are complementary: scanning provides repeatable breadth, while penetration testing examines exploitability and attack context.
Yes. Active scans interact directly with systems and can consume bandwidth, affect performance, or trigger unexpected failures. Before scanning production, review throttling and safe-check options, test the configuration in staging, and use read-only or out-of-band collection for systems that cannot tolerate disruption.
Because they may observe different evidence. One scanner may authenticate while the other does not, resolve package versions differently, or rely on a different advisory feed. Compare the evidence behind each finding rather than assuming either result is correct; authenticated access often improves accuracy, but it does not guarantee it.
Yes. A hardened base image is accurate on the day it is published, and new CVEs are disclosed against software that has not changed since. Scanning is what tells you that an image which passed six weeks ago now carries a critical finding. It also catches the drift between the image you approved and the container currently running.
Table of contents
- Key Takeaways
- What Are Vulnerability Scanning Tools?
- Key Features of Vulnerability Scanning Tools
- Types of Vulnerability Scanning Tools
- Top 10 Vulnerability Scanning Tools
- Benefits of Vulnerability Scanning
- Open Source Vulnerability Scanning Tools
- Choosing the Right Vulnerability Scanner
- How Orca Scans Cloud Estates Without Agents
- Frequently Asked Questions about Vulnerability Scanning Tools