OWASP Top 10 Scanner: How to Test Your Website (Free Tools Included)

What Is an OWASP Top 10 Scanner?

An OWASP scanner — specifically an OWASP Top 10 scanner — is a security tool that probes a running web application for the classes of weakness named in the OWASP Top 10 (broken access control, injection, security misconfiguration, and so on) and reports findings mapped back to those categories. The "OWASP Top 10" part is the differentiator. A generic vulnerability scanner spits out a flat list of issues; an OWASP-aware scanner organizes the same results into the categories your auditors, your PCI assessor, and your own backlog already speak in.

It helps to be precise, because three different things get called an "OWASP scanner":

• A DAST tool you run yourself. Dynamic Application Security Testing tools like OWASP ZAP attack a live app from the outside — sending malicious requests and reading the responses. ZAP is the reference implementation: free, open source, maintained under the OWASP umbrella. Powerful, but a tool you have to drive, configure, and interpret.
• A SaaS / hosted scanner. You point it at a URL, it runs the same class of dynamic checks on its own infrastructure, and hands you a report. Lower setup cost, less control, usually better reporting and triage.
• A point tool or check. A header checker, a TLS tester, a CVE lookup — each covers a slice of one category, not the whole list.

No single OWASP scanner covers all ten categories well, and a couple can't really be scanned at all. The practical goal isn't to find one magic tool; it's to assemble automated coverage where automation works and know exactly where you still have to test by hand. That's what the rest of this guide lays out: how to test OWASP Top 10 coverage on your own app, category by category.

If you're not yet clear on what each category actually means, read our companion guide OWASP Top 10 web vulnerabilities explained first — this article assumes you know what A01 through A10 are and focuses on how to test for them.

Why Test Specifically Against OWASP Top 10?

Because it's the most widely used baseline for web application security, and almost everyone downstream of you already uses it as the common vocabulary.

The Top 10 is referenced as a benchmark by major compliance and governance frameworks. PCI DSS expects web applications to be protected against the kinds of flaws it enumerates; ISO 27001 programs routinely point to it when defining secure-development and vulnerability-management controls. When an assessor asks "how do you ensure your app isn't vulnerable to injection or broken access control," answering in OWASP categories is the answer they're expecting.

There's a practical reason too. The Top 10 is a prioritization, not an exhaustive checklist — these are the failure modes that show up most often and hurt most when they do. Testing against it means spending your first hours on the issues most likely to be present, rather than chasing exotic bugs while an unauthenticated IDOR sits in your API.

So OWASP vulnerability scanning means two things: get coverage across all ten categories, and report findings in those categories so results plug straight into compliance evidence and your remediation workflow.

How to Test Each OWASP Top 10 Category

For each category below: what to test, how far automation gets you, what stays manual, and which tool fits. Treat it as a coverage map — most categories are scanner-friendly, two (A04, A08) are weak spots for any scanner.

A01 — Broken Access Control

What to test. Whether a user can reach data or actions they shouldn't: change /invoice/1001 to /invoice/1002 and see someone else's invoice (IDOR), hit an admin endpoint as a regular user (privilege escalation), or reach /admin directly without a link (forced browsing). Open redirect flaws also live near this category and overlap with A10. (If those terms aren't familiar, the OWASP Top 10 web vulnerabilities guide defines them.)

Automated test. A scanner can spider the app, hammer object IDs, and flag missing authorization — but only if it's authenticated with valid sessions for at least two roles, so it can detect that role A reaches role B's data.

Manual test. Authorization logic is business-specific, so the highest-value testing is manual: capture a request as a privileged account, replay it as an unprivileged one, confirm it's rejected. Repeat across sensitive actions.

Tool. ZAP (authenticated, multiple user contexts) for discovery; Burp/ZAP for manual replay; Exploita verifies each finding with a working proof-of-concept before reporting, cutting the "is this real?" noise that plagues access-control scanning.

A02 — Cryptographic Failures

What to test. The testable surface is mostly transport: outdated TLS versions, deprecated TLS 1.0, weak cipher suites, missing HSTS, and sensitive data sent over plain HTTP.

Automated test. TLS configuration is highly automatable — a scanner enumerates supported protocols and ciphers and flags anything obsolete. A quick manual check:

openssl s_client -connect example.com:443 -tls1

If that handshake succeeds, TLS 1.0 is still enabled and should be turned off. Note that recent OpenSSL builds often disable TLS 1.0/1.1 in the client, so a failed handshake here doesn't by itself prove the server has it off — confirm with nmap --script ssl-enum-ciphers -p 443 example.com, which reports the server's actual supported protocols and ciphers.

Manual test. At-rest encryption, key management, and whether sensitive fields are encrypted in the database aren't visible from outside — they need code and architecture review.

Tool. openssl / nmap ssl-enum-ciphers or a generic SSL/TLS testing tool for transport; the linked glossary entries explain exactly what to remediate.

A03 — Injection

What to test. Untrusted input reaching an interpreter — SQL injection, command injection, LDAP injection, and cross-site scripting (XSS, injection into the browser; merged into A03 in the 2021 revision). This is the category DAST tools were built for.

Automated test. Strong. A scanner fuzzes every parameter, header, and form field with injection payloads and watches for error signatures, time delays (blind SQLi), or reflected scripts.

Manual test. Stored/second-order injection (payload saved now, executed later) and injection behind complex multi-step flows often slip past automated crawlers — worth a manual pass on anything that persists user input.

Tool. SQLMap for SQLi depth, ZAP active scan for breadth, Nuclei for known patterns; Exploita exercises these injection points dynamically.

A04 — Insecure Design

What to test. Flaws in the design itself — missing rate limiting on a password reset, a logic loop that lets you buy an item for a negative quantity, trust boundaries that were never drawn.

Be honest: scanners are weak here. Insecure design is the absence of a control that should have existed. A scanner has no model of what your app is supposed to do, so it can't tell a missing control is missing. This category needs threat modeling and manual design review; the most a scanner contributes is catching downstream symptoms (e.g., missing rate limiting showing up as brute-forceability). Don't let a clean scan create false confidence.

A05 — Security Misconfiguration

What to test. Defaults and deployment mistakes: missing security headers, directory listing left enabled, verbose error pages leaking stack traces, clickjacking from absent X-Frame-Options/CSP, mixed content, default credentials, and exposed admin panels.

Automated test. Very automatable and a great quick win. Start with our free security headers checker — it flags missing or weak headers (CSP, HSTS, X-Frame-Options) in seconds.

Manual test. Confirm default accounts are removed, error verbosity is dialed down in production, and admin interfaces are network-restricted.

Tool. The headers checker for headers; ZAP and Nuclei for directory listing, default files, and exposed panels.

Ready to see where your app stands? Run a free OWASP Top 10 scan with Exploita — it maps every finding to its OWASP category and ships a verified proof-of-concept so you're not triaging guesses.

A06 — Vulnerable and Outdated Components

What to test. Known-vulnerable libraries, frameworks, plugins, and server software — an old jQuery, an unpatched CMS, a web server with a public CVE.

Automated test. Strong, and this is where CVE-aware scanning earns its keep. The scanner fingerprints observable components (response headers, JS libraries, framework signatures, CMS markers) and cross-references CVE databases. For dependencies you control, a Software Composition Analysis (SCA) tool reading your lockfiles catches more, since not every component is detectable from outside.

Manual test. Maintain an inventory of what you ship and reconcile it with what the scanner sees — external fingerprinting misses internal and transitive dependencies.

Tool. Nuclei (large CVE template library), SCA for dependencies; Exploita runs CVE checks on every scan and maps confirmed component vulnerabilities to A06.

A07 — Identification and Authentication Failures

What to test. Weak login defenses: no protection against credential stuffing or brute force, weak password policy, predictable or non-rotating session tokens, session fixation, broken password-reset flows.

Automated test. Partial. Scanners flag missing rate limiting, session cookies without Secure/HttpOnly/SameSite, and tokens that don't rotate after login.

Manual test. Multi-factor logic, account-recovery edge cases, and the full session lifecycle need a human walking the flows with a proxy.

Tool. ZAP for cookie/session attributes; manual review of the reset and MFA flows.

A08 — Software and Data Integrity Failures

What to test. Trusting code or data that hasn't been verified — unsigned updates, an insecure CI/CD pipeline, deserialization of untrusted data, third-party scripts loaded without Subresource Integrity (SRI).

Be honest: mostly out of scope for scanners. A DAST scanner can sometimes spot missing SRI or a deserialization endpoint, but the heart of this category — your build pipeline, signing, and update mechanisms — lives in infrastructure and process, not the app's HTTP surface. Cover it with pipeline hardening, dependency-integrity controls, and review; treat any scanner signal as a bonus, not coverage.

A09 — Security Logging and Monitoring Failures

What to test. Whether attacks are detected and recorded — are failed logins logged, do alerts fire, is there an audit trail for sensitive actions?

Automated test. Essentially none from the outside. By definition this is about what happens inside your systems, which an external scanner can't observe.

Manual test. Run a controlled attack (a burst of failed logins, an injection attempt), then check your logs and alerting. If nothing showed up, that's the finding — and skipping this check is itself the most common A09 failure.

Tool. Your SIEM / log pipeline plus a deliberate test exercise.

A10 — Server-Side Request Forgery (SSRF)

What to test. Whether the server can be tricked into making requests on the attacker's behalf — any feature that fetches a URL (webhooks, image-from-URL, PDF generators, link previews) pointed at internal addresses like 169.254.169.254 (cloud metadata) or localhost.

Automated test. Good and improving. Scanners inject internal/callback URLs into fetch-style parameters and watch for out-of-band callbacks or response differences. ZAP and Nuclei both have SSRF detection.

Manual test. SSRF often hides in non-obvious parameters and parsers; manually testing every URL-accepting input with internal targets and a callback server catches what crawlers miss.

Tool. ZAP/Nuclei with an interaction server; Exploita confirms SSRF with a proof-of-concept rather than reporting a maybe.

OWASP Top 10 testing — quick mapping

Category	What to test	Automated	Manual	Tool
A01 Broken Access Control	IDOR, privilege escalation, forced browsing	Partial (needs auth + 2 roles)	High value	ZAP (authenticated), Exploita, Burp/ZAP replay
A02 Cryptographic Failures	TLS version, weak ciphers, HSTS, plain HTTP	Strong (transport)	At-rest crypto	openssl, nmap ssl-enum-ciphers, SSL/TLS tester
A03 Injection	SQLi, command, XSS	Strong	Stored/second-order	SQLMap, ZAP active scan, Nuclei
A04 Insecure Design	Missing controls, logic flaws	Very weak	Required	Threat modeling, design review
A05 Security Misconfiguration	Headers, dir listing, errors, clickjacking	Strong	Defaults, admin access	Headers checker, ZAP, Nuclei
A06 Vulnerable Components	Outdated libs/frameworks/CVEs	Strong	Dependency inventory	Nuclei, SCA, Exploita (CVE)
A07 Auth Failures	Brute force, sessions, reset flow	Partial	MFA, recovery logic	ZAP, manual flow review
A08 Integrity Failures	SRI, deserialization, pipeline	Very weak	Required	Pipeline hardening, review
A09 Logging & Monitoring	Detection, alerting, audit trail	None	Required	SIEM + test exercise
A10 SSRF	URL-fetch features → internal targets	Good	Hidden parameters	ZAP/Nuclei + interaction server, Exploita

Automated OWASP Top 10 Scanners — Which to Choose

The scanner question is which engine carries the automatable load — open-source OWASP testing tools you run yourself versus a hosted scanner.

OWASP ZAP is the default open-source DAST tool: free, actively maintained, with authentication and scripting support and reports you can map to OWASP categories. The cost is operational — you configure contexts and policies and triage results yourself, and ZAP can be noisy, so budget time for false-positive validation.

Nuclei is template-driven and excellent for known patterns (CVEs, misconfigurations, exposed files). Fast and low-noise because each template encodes a deterministic check; the flip side is it finds what its templates describe, not novel injection or access-control logic. It pairs well with ZAP rather than replacing it.

Wapiti is a lighter open-source scanner — straightforward black-box crawling and injection testing, easy to run in CI, but with a smaller feature set than ZAP. Useful as a quick gate, not a complete program.

SaaS / hosted scanners trade control for convenience: no infrastructure or policies to manage, usually stronger reporting and triage, and good ones de-duplicate and prioritize. The questions to ask: what's the OWASP category coverage, does the report map findings to OWASP out of the box, what's the false-positive rate, and does it verify findings or just flag potential ones?

That last point is where unverified findings cost the most engineering time. Exploita runs DAST plus CVE checks, maps every result to its OWASP Top 10 category, and verifies each finding with a working proof-of-concept before it reaches your report — so a reported SQL injection or SSRF comes with evidence that it actually fires, not a "potential" you have to reproduce yourself. Full scans typically complete in around 12 minutes, and it's free to start.

No automated OWASP scanner — open source or hosted — covers A04, A08, or A09 meaningfully. Choose an engine for the eight categories where automation works and schedule manual review for the rest. For how dynamic scanning differs from static analysis, see DAST vs SAST.

Free Tools to Get Started Today

You can stand up meaningful OWASP Top 10 testing today with free tools — here are the four that give the most coverage per minute.

1. OWASP ZAP — the 3-step basics.

1. Install ZAP and set your browser to use it as a proxy (or use its built-in browser). Browse your app while authenticated so ZAP learns the URLs and captures a session.
2. Right-click the target in the Sites tree and run Spider to map endpoints, then Active Scan to launch the attacks.
3. Read the Alerts tab, sorted by risk. Validate each high/medium before acting — ZAP flags possibilities, and some are false positives.

That alone gives you injection, misconfiguration, and SSRF coverage. Configure authentication contexts to extend it toward access-control testing.

2. Zero-setup online scan. If you don't want to install anything, run a free OWASP Top 10 scan with Exploita — point it at a URL and get OWASP-categorized, proof-verified findings. Good as a fast baseline alongside ZAP, or as your main scan if you'd rather not operate tooling.

3. Security headers (A05) in seconds. Run the free security headers checker to catch missing CSP, HSTS, and X-Frame-Options. It's the fastest single check here and clears a real chunk of A05.

4. SSL/TLS (A02). Test transport security with openssl s_client, nmap --script ssl-enum-ciphers, or a generic SSL/TLS testing tool. The glossary entries on weak cipher suites and deprecated TLS 1.0 explain the remediation.

Browse the full free tools index for more point checks.

How Often to Run an OWASP Top 10 Scan

Cadence beats one-off scanning. A scan is a snapshot; your app changes constantly.

• After every significant release. New code is where new vulnerabilities arrive. Wire a scan into your deploy pipeline so each meaningful change gets tested.
• Weekly for critical production apps. A regular cadence catches drift — a dependency that picked up a new CVE, a config change that re-enabled directory listing — independent of your release schedule.
• On trigger events. A new public CVE in a framework you use, a change to authentication or access-control logic, or a new internet-facing feature (especially anything that fetches URLs — fresh SSRF surface) all justify an out-of-band scan.

A clean scan in March says nothing about your April code.

Common OWASP Scanning Mistakes

A few mistakes quietly gut the value of OWASP scanning:

• Scanning unauthenticated. If your OWASP scanner never logs in, it only sees the public surface and misses most of A01 and A07. Always configure authentication, ideally two roles, so it can test access control across privilege levels.
• Treating a clean scan as coverage of A04 and A08. Scanners are weak on insecure design and integrity failures. A green report there means the scanner found nothing it can find — not that you're safe. Threat modeling and review are non-optional.
• Acting on findings without validation. Open-source scanners produce false positives. Filing a ticket — or changing code — for an unverified finding wastes time and erodes trust in the scan. Reproduce before you remediate.
• Ignoring A09. Logging and monitoring don't show up in scan output, so they get forgotten. Run a deliberate attack and confirm your logs and alerts caught it.

From Scan to Fix — Next Steps

A scan that doesn't end in fixes is just an expensive list. Close the loop:

1. Triage by severity and OWASP category. Sort by risk first, then group by category so related issues get fixed together and your evidence lines up with how auditors think.
2. Validate before remediating. Confirm each finding is real; verified findings (with a PoC) skip this step.
3. Fix, then re-scan to confirm. Re-run the scan against the fixed issues specifically — re-test is the only proof the vulnerability is gone.
4. Make it a loop. Feed the cadence above back in so scanning is continuous, not a once-a-quarter fire drill.

For a structured walkthrough of turning raw findings into a prioritized remediation plan, see website vulnerability assessment. For the broader program this fits into, our pillar guide on web application security testing covers how scanning, manual testing, and process come together — and how to scan a website for vulnerabilities is a good starting point if you're new to running scans.

When you're ready, lean on a capable OWASP scanner to do the automatable work: run a free OWASP Top 10 scan with Exploita — DAST plus CVE checks, every finding mapped to its OWASP category and verified with a proof-of-concept, in about 12 minutes. Pair it with the free security headers checker for an instant A05 read.

Frequently Asked Questions

What are the best free OWASP Top 10 scanners? OWASP ZAP is the leading free DAST tool and the natural starting point — it covers injection, misconfiguration, and SSRF well and supports authenticated scanning. Pair it with Nuclei for CVE and known-pattern coverage (A06), the free security headers checker for A05, and openssl or nmap ssl-enum-ciphers for TLS (A02). Exploita offers a free zero-setup online scan that maps findings to OWASP categories and verifies each with a proof-of-concept. No single free tool covers all ten categories, so combine a few and reserve A04, A08, and A09 for manual review.

Is OWASP ZAP enough for a production app? ZAP is a strong, free DAST engine, but on its own it isn't a complete OWASP program for production. It needs careful authentication setup to test access control (A01) and auth failures (A07), it can be noisy with false positives that require validation, and it can't meaningfully cover insecure design (A04), integrity failures (A08), or logging and monitoring (A09). For production, supplement ZAP with CVE-aware scanning, manual review of the design and auth flows, and a tool that verifies findings so you're not triaging false positives by hand.

How long does a full OWASP Top 10 scan take? It depends on the size of the app and the tool. A thorough OWASP ZAP active scan on a non-trivial application can run from tens of minutes to several hours, especially with authenticated crawling. Hosted scanners are usually faster because they parallelize and tune the scan — an Exploita scan typically completes in around 12 minutes. Manual testing for A01, A04, A08, and A09 takes additional, separate time and isn't captured in the automated scan duration.

Should I run an OWASP scan in production or staging? Scan staging when you can — active scanning sends real attack payloads, which can create junk data, trigger side effects, or stress the system. Use a staging environment that mirrors production configuration so the results are representative. Some checks (like TLS and security headers, or read-only checks) are safe to run against production. If you must active-scan production, do it in a maintenance window, exclude destructive endpoints, and notify your team so the traffic isn't mistaken for a real attack.