Security - https://stackoverflow.com/users/login BeaverCheck Audit

F

Bot Challenge Detection

Action

Scan was blocked by Cloudflare -- the rest of this report does NOT reflect the real site

FIX

Scan was blocked by Cloudflare -- the rest of this report does NOT reflect the real site

Scan returned a Cloudflare bot-protection interstitial, not the actual page

The HTML captured by the scanner is a `Cloudflare` challenge / block page. The scanner's user-agent or IP was flagged as bot traffic and the real site content was never returned. Every other section in this report (security headers, accessibility, content, SEO, performance) was computed against the few KB of interstitial HTML rather than your actual page -- those findings are NOT meaningful for this URL. Detection signal: <title>Just a moment...</title> -- Cloudflare interactive challenge Resolution paths: (1) allow-list BeaverCheck's worker IPs at the bot-protection layer, (2) configure a relaxed challenge for known scanner user-agents, or (3) accept that the public site is unscannable from third-party tools. Note that Cloudflare's "Bot Fight Mode" and "Super Bot Fight Mode" both block the scanner by default.

Got: HTTP 200, title: Just a moment...

F

Subresource Integrity

Action

0 of 1 external resources have SRI

FIX

0 of 1 external resources have SRI

External script from challenges.cloudflare.com lacks integrity attribute

Without SRI, if this CDN is compromised, attackers could inject malicious code.

Got: https://challenges.cloudflare.com/turnstile/v0/g/fe6331af5207/api.js?onload=kwkA1&render=explicit

SRI Coverage 0 / 1 of external resources have integrity hashes

Tag	Domain	Integrity
<script>	challenges.cloudflare.com	✗ Missing

C

Security Headers

Action

5 of 10 headers properly configured

REVIEW

5 of 10 headers properly configured

Strict-Transport-Security is properly configured (consider adding preload)

Got: max-age=31536000; includeSubDomains

X-Content-Type-Options header is missing

This header prevents MIME-type sniffing, which can lead to XSS attacks. Set it to 'nosniff'.

Expected: nosniff

X-Frame-Options is properly configured

Got: SAMEORIGIN

Referrer-Policy header is missing

Controls how much referrer information is sent with requests. Set to 'strict-origin-when-cross-origin' or stricter.

Expected: strict-origin-when-cross-origin

Permissions-Policy header is missing

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

Expected: geolocation=(), camera=(), microphone=()

Content-Security-Policy is present

Got: upgrade-insecure-requests; frame-ancestors 'self' https://stackexchange.com

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

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

X-Powered-By header is not present

Server header is present without version info

Got: cloudflare

Domain is not in the Chrome HSTS preload list (status: unknown)

Submit your domain to hstspreload.org to close the trust-on-first-use gap. Requires a preload-ready HSTS header (max-age=31536000+, includeSubDomains, preload).

Got: unknown

This header prevents MIME-type sniffing, which can lead to XSS attacks. Set it to 'nosniff'.

Expected: nosniff

Why this matters

MIME sniffing lets browsers run uploaded files as JavaScript, turning a file upload into an XSS.

Learn more ▾

Setting X-Content-Type-Options: nosniff tells browsers to trust your declared Content-Type instead of guessing. Without it, an attacker who uploads a polyglot file can sometimes get it executed as a script. One header, no downside.

Source: OWASP / MDN

Controls how much referrer information is sent with requests. Set to 'strict-origin-when-cross-origin' or stricter.

Expected: strict-origin-when-cross-origin

Why this matters

Default browser behavior leaks full URLs (including query params and tokens) to every third-party resource — set a strict policy.

Learn more ▾

Without a Referrer-Policy header, browsers send the full referring URL with images, scripts, and fonts loaded from third-party origins. URLs containing tokens, user IDs, or session params end up in third-party logs. Set `Referrer-Policy: strict-origin-when-cross-origin` (or stricter) to limit leakage.

Source: MDN / W3C

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

Submit your domain to hstspreload.org to close the trust-on-first-use gap. Requires a preload-ready HSTS header (max-age=31536000+, includeSubDomains, preload).

Why this matters

Not in the Chrome preload list — first-time visitors over plain HTTP can be downgraded by a network attacker before HSTS kicks in.

Learn more ▾

The HSTS header only protects users who have already visited the site (TOFU window). Adding your domain to the Chrome preload list closes that gap so HSTS is enforced from the very first connection. Requires a preload-ready header (max-age=31536000+, includeSubDomains, preload) then submission at hstspreload.org. Inclusion ships in the next Chrome release after acceptance.

Source: hstspreload.org

B

Content Security Policy

3 of 10 CSP checks passed

REVIEW

3 of 10 CSP checks passed

Raw CSP policy

Got: upgrade-insecure-requests; frame-ancestors 'self' https://stackexchange.com

default-src directive is missing

default-src provides a fallback for other directives. Set it to restrict default resource loading.

Expected: default-src 'self'

No script-src or default-src to check for 'unsafe-inline'

No script-src or default-src to check for 'unsafe-eval'

No script-src or default-src to check for wildcard

object-src falls back to default-src

base-uri directive is missing

Without base-uri, attackers can inject a <base> tag to hijack relative URLs. Set it to 'self' or 'none'.

Expected: base-uri 'self'

frame-ancestors directive is set

Got: frame-ancestors 'self' https://stackexchange.com

form-action directive is missing

form-action restricts where forms can submit data, preventing form hijacking.

Expected: form-action 'self'

upgrade-insecure-requests is enabled

default-src provides a fallback for other directives. Set it to restrict default resource loading.

Expected: default-src 'self'

Why this matters

Security gaps expose your site and users to attacks, eroding trust.

Without base-uri, attackers can inject a <base> tag to hijack relative URLs. Set it to 'self' or 'none'.

Expected: base-uri 'self'

Why this matters

Missing base-uri in CSP leaves a base-tag injection attack path open even on otherwise strict policies.

Learn more ▾

A common omission: developers add CSP for script-src and frame-ancestors but forget base-uri. The result is a CSP that looks strict but lets an attacker rewrite every URL on the page via <base href>. Add `base-uri 'self'` to close the gap.

Source: MDN CSP

form-action restricts where forms can submit data, preventing form hijacking.

Expected: form-action 'self'

Why this matters

Security gaps expose your site and users to attacks, eroding trust.

Parsed Policy

upgrade-insecure-requests

frame-ancestors 'self'https://stackexchange.com

C

Cookie Security

Action

5 cookies analyzed, 11 checks passed

REVIEW

5 cookies analyzed, 11 checks passed

Cookie 'prov' has the Secure flag

Cookie 'prov' has the HttpOnly flag

Cookie 'prov' has SameSite=None

Cookie '__cflb' is missing the Secure flag

Without the Secure flag, this cookie can be sent over unencrypted HTTP, exposing it to interception.

Cookie '__cflb' has the HttpOnly flag

Cookie '__cflb' has SameSite=Lax

Cookie 'prov' is missing the Secure flag

Without the Secure flag, this cookie can be sent over unencrypted HTTP, exposing it to interception.

Cookie 'prov' has the HttpOnly flag

Cookie 'prov' has no SameSite attribute

Without an explicit SameSite attribute, browser default behavior varies. Set SameSite=Lax or Strict.

Cookie '__cf_bm' has the Secure flag

Cookie '__cf_bm' has the HttpOnly flag

Cookie '__cf_bm' has no SameSite attribute

Without an explicit SameSite attribute, browser default behavior varies. Set SameSite=Lax or Strict.

Cookie '_cfuvid' has the Secure flag

Cookie '_cfuvid' has the HttpOnly flag

Cookie '_cfuvid' has SameSite=None

5 cookies analyzed 2 critical 2 warnings

Name	Secure	HttpOnly	SameSite	Size	Issues
prov	✓	✓	None	40 B	2
__cflb	✗	✓	Lax	51 B	1
prov	✗	✓	—	40 B	2
__cf_bm	✓	✓	—	206 B	1
_cfuvid	✓	✓	None	121 B	—

C

security.txt

Action

No security.txt file found

REVIEW

No security.txt file found

security.txt (RFC 9116) provides a standardized way for security researchers to report vulnerabilities. Create one at /.well-known/security.txt with at least a Contact field.

Expected: /.well-known/security.txt

security.txt

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

B

CSP Inline-Style Readiness

2 inline style attribute(s) detected

REVIEW

2 inline style attribute(s) detected

Each `style=""` attribute forces `style-src 'unsafe-inline'` in any Content-Security-Policy, which negates most of CSP's XSS-mitigation value. 2 inline style(s) is low. Affected element types include: div. Move styles to a stylesheet; use CSS custom properties for runtime-dynamic values; or adopt a nonce/hash CSP policy. Most teams take the stylesheet path because it's also a maintainability win.

B

Trusted Types (XSS Sink Hardening)

Trusted Types not enabled

REVIEW

Trusted Types not enabled

Trusted Types (CSP3) is a Chrome 83+ defense that requires DOM-XSS sinks (innerHTML, document.write, eval, ...) to receive a typed-and-sanitized value rather than a raw string. Adding `Content-Security-Policy: require-trusted-types-for 'script'; trusted-types default` neutralizes most DOM-XSS even when a payload reaches a sink. Adoption is currently ~0.1% of pages so this is informational; a roll-out usually starts in report-only mode.

B

Email Security

DMARC: reject, SPF: ~all, DKIM

REVIEW

DMARC: reject, SPF: ~all, DKIM

DMARC policy is reject — strongest protection

SPF ends in ~all (soft fail)

Soft fail tells receivers to accept-but-mark unauthorized mail. Migrate to -all once you've confirmed all legitimate senders are listed (DMARC aggregate reports help verify).

DKIM configured (selectors: google, smtpapi, k1, s2, s1)

MTA-STS not configured

MTA-STS forces inbound mail to use TLS, preventing downgrade attacks. Requires both a TXT record at _mta-sts.<domain> and a policy file at https://mta-sts.<domain>/.well-known/mta-sts.txt.

TLS-RPT not configured

TLS-RPT (RFC 8460) lets MTAs report TLS-handshake failures, so you can detect and fix MTA-STS misconfigurations. Add a TXT record at _smtp._tls.<domain>.

BIMI not configured

BIMI (Brand Indicators for Message Identification) lets supporting clients (Gmail, Apple Mail, Yahoo) display your verified logo next to your messages. Optional but raises trust signals. Requires DMARC at p=quarantine or p=reject to be honored.

DMARC

Policy reject — strongest protection Record v=DMARC1; p=reject; pct=100; rua=mailto:dmarc-aggregates@stackoverflow.com; ruf=mailto:dmarc-forensics@stackoverflow.com; fo=1

Soft fail tells receivers to accept-but-mark unauthorized mail. Migrate to -all once you've confirmed all legitimate senders are listed (DMARC aggregate reports help verify).

Why this matters

Informational: a labeled value pair from the audit.

MTA-STS forces inbound mail to use TLS, preventing downgrade attacks. Requires both a TXT record at _mta-sts.<domain> and a policy file at https://mta-sts.<domain>/.well-known/mta-sts.txt.

Why this matters

Without MTA-STS, inbound mail can be silently downgraded to plain SMTP by a network attacker.

Learn more ▾

MTA-STS (RFC 8461) tells sending mail servers to use TLS and to refuse delivery if TLS fails. Requires both a TXT record at _mta-sts.<domain> AND a policy file at https://mta-sts.<domain>/.well-known/mta-sts.txt. Without it, an active attacker on the network path can strip STARTTLS and read the email in plaintext.

Source: RFC 8461

TLS-RPT (RFC 8460) lets MTAs report TLS-handshake failures, so you can detect and fix MTA-STS misconfigurations. Add a TXT record at _smtp._tls.<domain>.

Why this matters

Without TLS-RPT, you have no visibility into inbound TLS failures — MTA-STS misconfigurations stay hidden until users complain.

Learn more ▾

TLS-RPT (RFC 8460) is the feedback channel for MTA-STS: senders post aggregate reports of TLS-handshake failures to the URI in your _smtp._tls TXT record. Without it, an MTA-STS misconfiguration silently rejects mail and you find out only when someone notices missing email.

Source: RFC 8460

BIMI (Brand Indicators for Message Identification) lets supporting clients (Gmail, Apple Mail, Yahoo) display your verified logo next to your messages. Optional but raises trust signals. Requires DMARC at p=quarantine or p=reject to be honored.

Why this matters

Security gaps expose your site and users to attacks, eroding trust.

C

Permissions-Policy

Action

0 directives, 5 missing

REVIEW

0 directives, 5 missing

camera not restricted

Consider adding camera=() to block camera access from embedded content.

microphone not restricted

Consider adding microphone=() to block microphone access from embedded content.

geolocation not restricted

Consider adding geolocation=() to block geolocation access from embedded content.

payment not restricted

Consider adding payment=() to block payment access from embedded content.

usb not restricted

Consider adding usb=() to block usb access from embedded content.

Raw Header

microphone 'none'; speaker 'none'

Feature Permissions

Blocked Self Only Unrestricted Not Set

camera Not Set

microphone Not Set

geolocation Not Set

payment Not Set

usb Not Set

B

CORS Configuration

No CORS headers

REVIEW

No CORS headers

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+

TLS & Certificates

TLS 1.3, 7 checks passed

PASS

TLS 1.3, 7 checks passed

TLS 1.3 is used

Got: TLS 1.3

Strong cipher suite is used

Got: TLS_AES_128_GCM_SHA256

HTTP/2 is not negotiated

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

Got: http/1.1

OCSP stapling not enabled

Without stapling, the browser performs a separate OCSP roundtrip on first connection -- adding latency and leaking the visited host to the CA. Enable OCSP stapling on your TLS server.

Certificate is valid (expires in 69 days)

Got: 2026-07-18T13:32:17Z

Certificate chain has 2 certificates

Certificate uses modern signature algorithm

Got: ECDSA-SHA384

Certificate covers 2 domain(s)

Got: *.stackoverflow.com, stackoverflow.com

Certificate is issued by a trusted CA

Got: CN=E7,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

Without stapling, the browser performs a separate OCSP roundtrip on first connection -- adding latency and leaking the visited host to the CA. Enable OCSP stapling on your TLS server.

Why this matters

Without OCSP stapling, every first-time visitor pays an extra OCSP roundtrip — and the CA learns who's visiting your site.

Learn more ▾

OCSP stapling has the server fetch its own revocation status from the CA and attach the signed response to the TLS handshake. Without it, browsers contact the CA directly: extra latency for the user and a privacy leak (the CA sees who connected). Enable ssl_stapling on (nginx) / SSLUseStapling On (Apache) / OCSPStapling = on (Caddy auto-enables).

Source: RFC 6961 / Mozilla Server-Side TLS guide

Connection

Protocol

TLS 1.3

Cipher Suite

TLS_AES_128_GCM_SHA256

HTTP Version

HTTP/1.1

Certificate Chain

Leaf Certificate

Subject CN=stackoverflow.comIssuer CN=E7,O=Let's Encrypt,C=USValid 2026-04-19T13:32:18Z → 2026-07-18T13:32:17ZExpires in 69 days SANs *.stackoverflow.com, stackoverflow.comSignature ECDSA-SHA384Serial 68b9728525592cdf2fbda8dc592edf391ea

Intermediate (CA Certificate)

Subject CN=E7,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 306 days Signature SHA256-RSASerial aa75f1e62b8f0a220966d38bbfd4baa1

A+

Cookie Hygiene

All 5 cookie(s) pass hygiene checks

PASS

All 5 cookie(s) pass hygiene checks

A

WAF / Bot Protection

Cloudflare

PASS

Cloudflare

Cloudflare detected

Detected via: cf-ray: 9f97bca9df859f03-CDG

Got: Cloudflare

A+

Cross-Origin Tab Safety

All 2 new-tab link(s) carry rel=noopener

PASS

All 2 new-tab link(s) carry rel=noopener

A+

Soft-404 Detection

No soft-404 patterns detected in page title or headings

PASS

No soft-404 patterns detected in page title or headings

A+

Empty Page Detection

Page has substantive body text and no placeholder / template-leak signals

PASS

Page has substantive body text and no placeholder / template-leak signals

A+

Geo-Restriction Detection

No geo-restriction signals detected -- scan reached the page from an allowed region

PASS

No geo-restriction signals detected -- scan reached the page from an allowed region

No geo-restriction detected

A+

Maintenance Mode Detection

No maintenance-mode signals detected -- scan reached a normal page

PASS

No maintenance-mode signals detected -- scan reached a normal page

No maintenance-mode signals detected

A+

Source Map Exposure

Source-map probe didn't run on this scan

PASS

Source-map probe didn't run on this scan

A+

HTML Version Disclosure

No software-version disclosures in HTML

PASS

No software-version disclosures in HTML

A+

Open Redirect Surface

No redirect-shaped query parameters in DOM links

PASS

No redirect-shaped query parameters in DOM links

A+

Auth Security

Page is not a login form -- auth-security checks are N/A

PASS

Page is not a login form -- auth-security checks are N/A

Page does not appear to be a login form

A+

Subdomain Inventory Exposure

No risky subdomain names in certificate SANs

PASS

No risky subdomain names in certificate SANs

A+

JS Library Vulnerabilities

No known vulnerabilities

PASS

No known vulnerabilities

No known JavaScript library vulnerabilities detected

No known JavaScript library vulnerabilities detected.

A+

Information Leakage

No exposures

PASS

No exposures

No security.txt found

Consider adding a security.txt at /.well-known/security.txt.

No sensitive files exposed

No sensitive files exposed — all paths returned 404.

Path	Status	Category	Risk
/.git/HEAD	✓ Not found	Version Control	—
/.git/config	✓ Not found	Version Control	—
/.svn/entries	✓ Not found	Version Control	—
/.env	✓ Not found	Configuration	—
/.env.local	✓ Not found	Configuration	—
/.env.production	✓ Not found	Configuration	—
/wp-config.php	✓ Not found	Configuration	—
/.htaccess	✓ Not found	Configuration	—
/phpinfo.php	✓ Not found	Debug	—
/server-status	✓ Not found	Debug	—
/server-info	✓ Not found	Debug	—
/.well-known/security.txt	✓ Not found	Security Policy	—
/package.json	✓ Not found	dependency-manifest	—
/composer.json	✓ Not found	dependency-manifest	—
/Gemfile	✓ Not found	dependency-manifest	—
/Gemfile.lock	✓ Not found	dependency-manifest	—
/requirements.txt	✓ Not found	dependency-manifest	—
/pom.xml	✓ Not found	dependency-manifest	—
/.gitlab-ci.yml	✓ Not found	ci-config	—
/.travis.yml	✓ Not found	ci-config	—

A+

API Surface

No API specs or GraphQL introspection found (probed 11 candidate path(s))

PASS

No API specs or GraphQL introspection found (probed 11 candidate path(s))

No API specs or GraphQL introspection found (probed 11 path(s))

A

Transport Security

HTTP/3, HSTS, and TLS version analysis

PASS

HTTP/3, HSTS, and TLS version analysis

HTTP/3 (QUIC) not advertised

HTTP/3 eliminates head-of-line blocking. If your CDN supports it, consider enabling it.

HSTS enabled (includeSubDomains)

TLS 1.3 in use (fastest handshake, 1-RTT)