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Security

· 12 checks — HTTP headers, CSP, TLS handshake, and cookie hygiene rolled into one auditable list.
SCORE
84
GRADE
B
FIX
2
REVIEW
2
PASS
8
INFO
0
Checks
12
8 PASS 2 REVIEW 2 FIX
D
Permissions-Policy
Action
No header set
FIX
No header set
Warning::
No Permissions-Policy header
Consider adding a Permissions-Policy header to restrict browser feature access from embedded content.

No Permissions-Policy header set.

Without this header, embedded iframes can request access to sensitive device features.

Suggested header
Permissions-Policy: camera=(), microphone=(), geolocation=(), payment=(), usb=()
D
security.txt
Action
No /.well-known/security.txt published
FIX

security.txt

No security.txt found at /.well-known/security.txt

B
Security Headers
6 of 10 headers properly configured
REVIEW
6 of 10 headers properly configured
Warning::
HSTS is missing includeSubDomains
Without includeSubDomains, subdomains can still be accessed over HTTP.
Got: max-age=31557600 Expected: max-age=31536000; includeSubDomains
Info::
X-Content-Type-Options is properly configured
Got: nosniff
Info::
X-Frame-Options is properly configured
Got: DENY
Info::
Referrer-Policy is properly configured
Got: strict-origin-when-cross-origin
Warning::
Permissions-Policy header is missing
Controls which browser features (camera, microphone, geolocation) are allowed. Set it to restrict unused features.
Expected: geolocation=(), camera=(), microphone=()
Info::
Content-Security-Policy is present
Got: base-uri 'none'; default-src 'none'; frame-ancestors 'none'; font-src 'self' htt…
Warning::
Cross-Origin-Opener-Policy header is missing
COOP isolates your browsing context, preventing cross-origin side-channel attacks. Set to 'same-origin'.
Expected: same-origin
Warning::
Cross-Origin-Embedder-Policy header is missing
COEP prevents loading cross-origin resources without explicit permission. Required for SharedArrayBuffer and high-resolution timers.
Expected: require-corp
Info::
X-Powered-By header is not present
Info::
Server header is present without version info
Got: Mastodon

Without includeSubDomains, subdomains can still be accessed over HTTP.

Expected: max-age=31536000; includeSubDomains
Why this matters

Without includeSubDomains, a forgotten dev subdomain over HTTP can set malicious cookies that ride to the apex.

Learn more ▾

HSTS without includeSubDomains protects only the exact domain. Cookies set on a non-HSTS subdomain can ride to the apex via cookie-scope attacks. The fix is one directive append. Verify all subdomains support HTTPS first — adding includeSubDomains to a domain with HTTP-only subdomains breaks them.

Source: RFC 6797

Controls which browser features (camera, microphone, geolocation) are allowed. Set it to restrict unused features.

Expected: geolocation=(), camera=(), microphone=()
Why this matters

Permissions-Policy locks down browser APIs you don't use — without it, every page can request camera/mic/geolocation if XSS lands.

Learn more ▾

By default every page can request the camera, microphone, geolocation, payment APIs, and dozens more. Permissions-Policy turns off the ones you don't need so a future bug can't quietly start using them. It's a defense-in-depth header — one line, big surface reduction.

Source: MDN / W3C

COOP isolates your browsing context, preventing cross-origin side-channel attacks. Set to 'same-origin'.

Expected: same-origin
Why this matters

COOP isolates your top-level browsing context from cross-origin windows — without it, popup-based side-channel attacks remain possible.

Learn more ▾

Cross-Origin-Opener-Policy: same-origin prevents cross-origin pages from sharing a browsing-context group with yours. This blocks cross-window references that enable Spectre-style timing attacks and tab-nabbing. Required if you want to enable SharedArrayBuffer.

Source: MDN / web.dev

COEP prevents loading cross-origin resources without explicit permission. Required for SharedArrayBuffer and high-resolution timers.

Expected: require-corp
Why this matters

COEP enforces that all embedded resources opt-in to cross-origin embedding — required for cross-origin isolation features.

Learn more ▾

Cross-Origin-Embedder-Policy: require-corp ensures every embedded resource (script, iframe, image) explicitly allows being loaded cross-origin. Combined with COOP, this enables the cross-origin-isolated context that unlocks SharedArrayBuffer, high-resolution timers, and other powerful APIs.

Source: MDN / web.dev

B
CORS Configuration
No CORS headers
REVIEW
No CORS headers
Info::
No CORS headers present — secure default
CORS Configuration ✓ Secure

No CORS headers detected.

Cross-origin requests are blocked by browser same-origin policy.

Origin reflection test

Some servers mirror the request Origin header, which can be exploited. Test manually:

curl -sI -H "Origin: https://evil.com" <url> | grep -i access-control
A+
Content Security Policy
8 of 10 CSP checks passed
PASS
8 of 10 CSP checks passed
Info::
Raw CSP policy
Got: base-uri 'none'; default-src 'none'; frame-ancestors 'none'; font-src 'self' https://mastodon.social; img-src 'self' data: blob: https://mastodon.social https://files.mastodon.social; media-src 'self' data: https://mastodon.social https://files.mastodon.social; manifest-src 'self' https://mastodon.social; form-action 'none'; child-src 'self' blob: https://mastodon.social; worker-src 'self' blob: https://mastodon.social; connect-src 'self' data: blob: https://mastodon.social https://files.mastodon.social wss://streaming.mastodon.social; frame-src 'self' https:; style-src 'self' https://mastodon.social 'nonce-uOICEEEMF3UIw25JxvJ1Gg=='; script-src 'self' https://mastodon.social 'wasm-unsafe-eval' 'sha256-Z5KW83D+6/pygIQS3h9XDpF52xW3l3BHc7JL9tj3uMs='
Info::
default-src directive is set
Got: default-src 'none'
Info::
No 'unsafe-inline' in script source
Info::
No 'unsafe-eval' in script source
Info::
No wildcard in script source
Info::
object-src falls back to default-src
Info::
base-uri is properly restricted
Got: base-uri 'none'
Info::
frame-ancestors directive is set
Got: frame-ancestors 'none'
Info::
form-action directive is set
Got: form-action 'none'
Info::
upgrade-insecure-requests is not set
This directive upgrades HTTP resources to HTTPS automatically, preventing mixed content.
Expected: upgrade-insecure-requests

This directive upgrades HTTP resources to HTTPS automatically, preventing mixed content.

Expected: upgrade-insecure-requests
Why this matters

Without upgrade-insecure-requests, any HTTP subresource link survives as a mixed-content warning instead of auto-upgrading.

Learn more ▾

Adding `upgrade-insecure-requests` to your CSP turns every http:// subresource fetch into https:// at the browser layer. One-line defense against accidental mixed content from legacy links or third-party widgets.

Source: MDN CSP

Parsed Policy

base-uri 'none'
default-src 'none'
frame-ancestors 'none'
font-src 'self'https://mastodon.social
img-src 'self'data:blob:https://mastodon.socialhttps://files.mastodon.social
media-src 'self'data:https://mastodon.socialhttps://files.mastodon.social
manifest-src 'self'https://mastodon.social
form-action 'none'
child-src 'self'blob:https://mastodon.social
worker-src 'self'blob:https://mastodon.social
connect-src 'self'data:blob:https://mastodon.socialhttps://files.mastodon.socialwss://streaming.mastodon.social
frame-src 'self'https:
style-src 'self'https://mastodon.social'nonce-uOICEEEMF3UIw25JxvJ1Gg=='
script-src 'self'https://mastodon.social'wasm-unsafe-eval''sha256-Z5KW83D+6/pygIQS3h9XDpF52xW3l3BHc7JL9tj3uMs='
A+
TLS & Certificates
TLS 1.3, 7 checks passed
PASS
TLS 1.3, 7 checks passed
Info::
TLS 1.3 is used
Got: TLS 1.3
Info::
Strong cipher suite is used
Got: TLS_AES_128_GCM_SHA256
Info::
HTTP/2 is not negotiated
HTTP/2 provides multiplexing and header compression for better performance.
Got: http/1.1
Info::
Certificate is valid (expires in 56 days)
Got: 2026-06-17T16:53:17Z
Info::
Certificate chain has 2 certificates
Info::
Certificate uses modern signature algorithm
Got: SHA256-RSA
Info::
Certificate covers 3 domain(s)
Got: files.mastodon.social, mastodon.social, www.mastodon.social
Info::
Certificate is issued by a trusted CA
Got: CN=R13,O=Let's Encrypt,C=US

HTTP/2 provides multiplexing and header compression for better performance.

Why this matters

HTTP/1.1 forces the browser to make sequential requests, multiplying latency on every page.

Learn more ▾

HTTP/2 (and HTTP/3) multiplex many requests over a single connection, eliminating head-of-line blocking. HTTP/1.1 forces the browser to either queue requests or open many parallel connections — both worse. Most modern web servers support HTTP/2 with one config line.

Source: MDN Web Docs

Connection
Protocol
TLS 1.3
Cipher Suite
TLS_AES_128_GCM_SHA256
HTTP Version
HTTP/1.1

Certificate Chain

Leaf Certificate
Subject CN=mastodon.socialIssuer CN=R13,O=Let's Encrypt,C=USValid 2026-03-19T16:53:18Z → 2026-06-17T16:53:17ZExpires in 56 days SANs files.mastodon.social, mastodon.social, www.mastodon.socialSignature SHA256-RSASerial 51dfc68a34762277ca1b1c2364e56d305ac
Intermediate (CA Certificate)
Subject CN=R13,O=Let's Encrypt,C=USIssuer CN=ISRG Root X1,O=Internet Security Research Group,C=USValid 2024-03-13T00:00:00Z → 2027-03-12T23:59:59ZExpires in 325 days Signature SHA256-RSASerial 5a00f212d8d4b480f3924157ea298305
A+
Cookie Security
No cookies set — no cookie security risks
PASS
No cookies set — no cookie security risks
Info::
No cookies set — no cookie security risks

No cookies detected — no cookie security risks to report.

A+
Subresource Integrity
No external resources
PASS
No external resources
Info::
No external resources to protect
SRI Coverage No external resources — SRI not applicable
A+
JS Library Vulnerabilities
No known vulnerabilities
PASS
No known vulnerabilities
Info::
No known JavaScript library vulnerabilities detected

No known JavaScript library vulnerabilities detected.

A+
Information Leakage
No exposures
PASS
No exposures
Info::
No security.txt found
Consider adding a security.txt at /.well-known/security.txt.
Info::
No sensitive files exposed

No sensitive files exposed — all paths returned 404.

PathStatusCategoryRisk
/.git/HEAD✓ Not foundVersion Control—
/.git/config✓ Not foundVersion Control—
/.svn/entries✓ Not foundVersion Control—
/.env✓ Not foundConfiguration—
/.env.local✓ Not foundConfiguration—
/.env.production✓ Not foundConfiguration—
/wp-config.php✓ Not foundConfiguration—
/.htaccess✓ Not foundConfiguration—
/phpinfo.php✓ Not foundDebug—
/server-status✓ Not foundDebug—
/server-info✓ Not foundDebug—
/.well-known/security.txt✓ Not foundSecurity Policy—
A
Email Security
DMARC: quarantine
PASS
DMARC: quarantine
Info::
DMARC policy is quarantine — good protection
DMARC
Policy quarantine — good protection Record v=DMARC1; p=quarantine; pct=100; rua=mailto:re+qkqn5debzpq@dmarc.postmarkapp.com; sp=none; aspf=r;
A+
Transport Security
HTTP/3, HSTS, and TLS version analysis
PASS
HTTP/3, HSTS, and TLS version analysis
Info::
HTTP/3 (QUIC) supported
The server advertises HTTP/3 via Alt-Svc for faster connections on mobile networks.
Info::
HSTS enabled (base policy)
Info::
HSTS missing includeSubDomains
Without includeSubDomains, HSTS only protects the exact domain.
Info::
TLS 1.3 in use (fastest handshake, 1-RTT)
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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