Free Public Network Security Scan
Free tool
Read-only scan of your public domain for open ports (a TCP connect check), subdomain takeover risk, and DNS posture (CAA, wildcards). No exploitation, safe to run against production.
- Open ports
- Subdomain takeover
- DNS security
No credit card requiredRead-only, no exploitationNo setup or code required
Used by 5,000+ developers and engineering teams
What this scan checks
- Open ports exposure on common services
- Subdomain takeover risk patterns
- DNS security posture (CAA presence, wildcards)
Why network exposure matters
Unnecessary open services and stale DNS records expand your attack surface. Tightening exposure at the edge and cleaning up DNS reduce both opportunistic and targeted attack paths.
How Barrion verifies this
Barrion checks your public attack surface from the outside in. We resolve your domain, then open TCP connections to a set of 38 common database, admin and service ports on the target host to see which ones answer. We don't send exploit payloads or credential-guessing traffic.
For subdomain takeover, we follow every CNAME chain and compare the final target against a fingerprint set of third-party services (S3, Azure, GitHub Pages, Heroku, and others) that return takeover-indicative responses when the backing resource is gone. A subdomain only flags when the DNS still points somewhere but the upstream provider reports the resource as unclaimed.
For DNS posture we look for CAA records that restrict certificate issuance and flag wildcard records that broaden the attack surface. DNSSEC isn't validated. All checks are read-only and safe to run against production.
How to reduce exposure
- Close unused ports at the firewall or load balancer
- Restrict admin panels by IP/VPN and enforce MFA
- Remove orphaned CNAMEs, and add CAA restricting certificate issuance
Tool-specific questions
Is the scan intrusive?
No. We use lightweight checks on common ports and public DNS.
Why are open ports risky?
Open ports can expose services to the internet, increasing the chance of exploitation, brute force, or data exposure. Close unused ports and restrict access to reduce risk.
What is subdomain takeover?
It occurs when a DNS record (like a CNAME) points to a resource that no longer exists. Attackers can claim the resource and serve content under your subdomain. Remove stale records to prevent this.
Do I need DNSSEC and CAA?
DNSSEC helps prevent tampering with DNS responses. CAA restricts which certificate authorities can issue certs for your domain. Both improve domain integrity and reduce mis-issuance.
Why Barrion
Built for the engineers who already have enough to fix.
Speed
Fast results
Instant analysis with a detailed report. You see findings as the scan runs, not after.
Coverage
Comprehensive checks
The full passive scan runs 18 checks on the free plan, covering TLS, headers and cookies. Paid plans run 35+ and add CORS, DNS, email auth and more.
Action
Step-by-step fixes
Every finding ships with the exact remediation step for your framework. Hand it to the engineer who owns the surface.
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More free checks, for the rest of your surface.
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FAQ
Frequently asked.
What is Barrion?
Barrion runs continuous, agentic AI penetration tests of web applications and APIs. AI agents test your app the way an attacker would, safely, on a schedule or on demand. Findings are checked against the live app before they're reported, and tracked across runs as new, still open, resolved or regressed. From Standard level up, a security engineer reviews each report. Barrion AB is based in Gothenburg, Sweden. A free passive scan is the quickest way to start.
How safe is Barrion to use for security testing?
AI pentests send real test requests, so they're rate-limited and non-destructive, and you approve the exact scope before a single request goes out. You can point them at staging too. The free passive scan only reads your live app. It never submits forms, brute-forces endpoints or touches anything that changes state, so it's safe to run against production.
What types of security issues does Barrion identify?
AI pentests look for the issues an attacker could exploit, like SQL injection, cross-site scripting and broken access control. Findings are checked against your live app, and confirmed ones come with the request and response that prove them. Anything we couldn't confirm is clearly marked and capped in severity. The passive scan catches misconfigurations in TLS and HTTPS, security headers, cookie flags, CORS policy, DNS records, email authentication (SPF, DKIM, DMARC) and network exposure.
What specific security checks does Barrion perform?
Barrion covers two surfaces. AI pentesting is the active part: specialist agents chain requests to find exploitable flaws such as SQL injection, cross-site scripting and broken access control. Findings are checked against your live app, and confirmed ones come with the request and response that prove them. The passive scan is read-only and safe to point at production. On paid plans it runs 35+ checks (18 on the free plan): transport security (HTTPS, HSTS, TLS version, cipher suites, certificate expiry, hostname and chain validity, OCSP stapling), HTTP response headers (Referrer-Policy, Permissions-Policy, X-Content-Type-Options, Content-Type, server information disclosure), CSP and framing (Content-Security-Policy, bypass detection, Trusted Types, X-Frame-Options), cross-origin policy (COOP, COEP, CORP and the full CORS header set), cookie flags and anti-CSRF tokens, mixed content, vulnerable JavaScript libraries, DNS records including DNSSEC and CAA, email authentication (SPF, DKIM, DMARC), open ports and subdomain takeover. Findings from both are ranked by severity and come with step-by-step remediation.
Will my auditor or enterprise customers accept the pentest report?
The report maps every finding to OWASP WSTG, a security engineer reviews it from Standard up and signs it off from Deep up, and a free retest shows what you fixed. Teams use it as evidence for SOC 2, ISO 27001 and NIS2 work. Whether it's accepted is up to your auditor.
How often does Barrion test my app?
Continuously or on demand. On the Business plan you save a pentest and it reruns daily, weekly, monthly, quarterly, every six months, yearly or on your own rhythm. On any plan you can start a pentest or a passive scan on demand. A passive scan also runs on a schedule and alerts you when something new shows up.
Is Barrion suitable for security testing of all business sizes?
Yes. Solo developers often start with the free passive scan and a single pentest. Teams with several apps run pentests on a schedule, and it fits alongside the tools you already run.
How does Barrion handle data security and privacy during security testing?
Passive scans are read-only: they only look at what your app already exposes publicly. For AI pentests we keep the findings in your report, and confirmed findings include the request and response behind them, so you can review and reproduce them. Test credentials you add are encrypted. Barrion is hosted in Sweden, data is stored in the EU and AI processing runs in the EU. Our trust page lists every subprocessor. Pentests are rate-limited and only run inside the scope you approve.
What if I'm not satisfied with Barrion's security testing service?
You can cancel anytime in the dashboard, and paid plans carry a 14-day refund window from the first charge. If something isn't right, contact us and we'll make it work for your team.
How does Barrion help with SOC 2, ISO 27001, NIS2, and other compliance frameworks?
Barrion's pentest reports come as PDF, XLSX and JSON, mapped to all 97 OWASP WSTG test cases, with engineer review from Standard up, sign-off from Deep up and a free retest after fixes. Teams use them as evidence that supports SOC 2, ISO 27001, PCI DSS and NIS2 work. Whether a report is accepted is up to your auditor or customer.
Anything else? Email contact@barrion.io.
Keep it covered
Fix it once, then watch it stay fixed.
A pentest shows what is exploitable today. A scheduled passive scan re-checks this tool's results and alerts you when a deploy undoes the fix.
What you get for free
18 core security checks via this tool, passive scans, step-by-step remediation, security score on every result.
What Essential adds from €199/mo
Pentest credits every month, +17 advanced checks, weekly passive scans, email alerts and audit-ready PDFs for SOC 2 / ISO 27001 / PCI.