Overview
Findings
Actions
Details
Related
AI-Generated Summary
What this means
castle.io scored 85/100, demonstrating a strong security posture. Minor improvements are noted below.
Positive signals: Known Breaches, TLS Configuration, HSTS Header all passed.
3 action items identified, including 0 critical. The issues are configuration gaps, not architectural problems. A focused remediation effort of 2–5 days could address all findings.
How castle.io compares
Grade distribution across 2378 companies we've scanned. castle.io scores better than 78% of them.
71
A+
22
A
180
A-
181
B+
69
B
333
B-
111
C+
111
C
295
C-
110
D+
92
D
216
D-
587
F
castle.io — Grade B (85/100)
2378 companies scanned
Security checks
Each check inspects a different part of castle.io's public security setup. Green means healthy, yellow needs attention, red is a problem.
DMARC / Email Security
Strengths: SPF record present with hard-fail (-all); DKIM configured (selectors: google, s1, s2). Issues: DMARC policy is 'none' (monitoring only, no enforcement).
DNS Configuration
Strengths: 4 nameservers configured (ns-712.awsdns-25.net., ns-77.awsdns-09.com., ns-1523.awsdns-62.org., ns-1818.awsdns-35.co.uk.); 5 MX records present; Zone transfers properly restricted. Issues: DNSSEC not configured — DNS responses can be spoofed.
Security Headers
3/5 security headers present. Missing: CSP, Permissions-Policy.
TLS Configuration
TLSv1.3 negotiated with TLS_AES_128_GCM_SHA256 (128-bit). Strong configuration with no deprecated protocols or weak ciphers detected.
Known Breaches
No known breaches found in public disclosure databases.
HSTS Header
HSTS enabled: max-age=31536000. Missing includeSubDomains. Missing preload directive.
CVE Exposure
Detected technologies: Netlify, Astro/v5.13.7. (Netlify detected but excluded from CVE matching — upstream infrastructure). No high or critical CVEs found for detected versions.
Certificate Hygiene
Strengths: Certificate valid, 65 days remaining; Issued by Let's Encrypt.
Recommended actions
3 items
Steps to improve castle.io's security grade, ranked by impact.
1
Strengthen email authentication configuration
Email authentication is partially configured for castle.io but has gaps. Actions needed: upgrade DMARC policy from 'none' to 'quarantine' or 'reject'. Until DMARC enforcement is active, spoofed emails may still reach recipients.
Compliance impact
NIST CSFPR.AC-7
Email authentication is a required access control
How to fix this
1
Upgrade DMARC policy to p=quarantine (then p=reject after monitoring)
2
Verify with: nslookup -type=txt _dmarc.castle.io
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2
Enable DNSSEC on your domain
Without DNSSEC, DNS responses for castle.io can be spoofed, potentially redirecting users to malicious sites. This requires coordination with your domain registrar to publish DS records.
Compliance impact
NIST 800-53SC-20
Secure name/address resolution service
How to fix this
1
Check if your DNS provider supports DNSSEC (Cloudflare, Route53, etc.)
2
Enable DNSSEC signing in your DNS provider dashboard
3
Add the DS record to your registrar for .io TLD
4
Verify: dig +dnssec castle.io
3
Add optional security headers (CSP, Permissions-Policy)
castle.io has most security headers configured. Missing: CSP, Permissions-Policy. These are best-practice additions that reduce the attack surface for client-side vulnerabilities.
How to fix this
1
Add Content-Security-Policy header (start with report-only to avoid breakage)
2
Add: Permissions-Policy: camera=(), microphone=(), geolocation=()
3
Verify with: curl -sI https://castle.io | grep -iE 'content-security|x-frame|x-content|referrer|permissions'
At a glance
Key data points from the scan.
TLS Version
TLSv1.3
TLSv1.3 negotiated with TLS_AES_128_GCM_SHA256 (128-bit). Strong configuration with no deprecated protocols or weak ciphers detected.
DMARC Policy
p=none
Strengths: SPF record present with hard-fail (-all); DKIM configured (selectors: google, s1, s2). Issues: DMARC policy is 'none' (monitoring only, no enforcement).
SPF Record
Present
v=spf1 include:_spf.google.com include:sendgrid.net include:spf.mail.intercom.io include:aspmx.pardo
Security Headers
3/5 present
Missing: CSP, Permissions-Policy
HSTS
Enabled
HSTS enabled: max-age=31536000. Missing includeSubDomains. Missing preload directive.
SSL Certificate
Valid
Strengths: Certificate valid, 65 days remaining; Issued by Let's Encrypt.
DNSSEC
Not enabled
Strengths: 4 nameservers configured (ns-712.awsdns-25.net., ns-77.awsdns-09.com., ns-1523.awsdns-62.org., ns-1818.awsdns-35.co.uk.); 5 MX records present; Zone transfers properly restricted. Issues: DNSSEC not configured — DNS responses can be spoofed.