Security - https://skyscanner.net BeaverCheck Audit

F

Security Headers

Action

2 of 10 headers properly configured

FIX

2 of 10 headers properly configured

Strict-Transport-Security is properly configured

Got: max-age=31536000; includeSubdomains; preload

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 header is missing

This header prevents clickjacking by controlling who can embed your page in a frame. Set it to DENY or SAMEORIGIN.

Expected: DENY

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 header is missing

CSP is the most important header for preventing XSS attacks. See the CSP section for detailed analysis.

Expected: default-src 'self'

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 reveals version information

The Server header discloses the software version, aiding attackers in targeting known vulnerabilities. Remove the version number.

Got: Apache/2.4.66 () OpenSSL/1.0.2k-fips

Domain is in the Chrome HSTS preload list (status: preloaded)

Got: preloaded

CSP is the most important header for preventing XSS attacks. See the CSP section for detailed analysis.

Expected: default-src 'self'

Why this matters

Without a CSP, a single XSS bug can exfiltrate everything your users type — including credentials.

Learn more ▾

Content-Security-Policy is the browser-enforced firewall against XSS. With a strict CSP, a script injection that would otherwise steal session cookies or rewrite the page is silently blocked. Without it, your only defense is hoping every input on every form is escaped correctly forever.

Source: OWASP / MDN

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

This header prevents clickjacking by controlling who can embed your page in a frame. Set it to DENY or SAMEORIGIN.

Expected: DENY

Why this matters

Without frame protection, your site can be embedded in a hostile page and used for clickjacking.

Learn more ▾

Clickjacking overlays your site under a transparent malicious page so users click invisible buttons. Setting X-Frame-Options: DENY (or a modern frame-ancestors CSP directive) blocks the embedding entirely. There's almost never a legitimate reason to allow it.

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

The Server header discloses the software version, aiding attackers in targeting known vulnerabilities. Remove the version number.

Why this matters

Server: nginx/1.18.0 tells attackers exactly which CVEs to test — strip the version string.

Learn more ▾

Server version disclosure helps attackers select exploits matching your stack. Configure your server to omit the version (nginx: `server_tokens off;`, Apache: `ServerTokens Prod`). Doesn't fix vulnerabilities but removes the easy reconnaissance step.

Source: OWASP

F

Content Security Policy

Action

No enforcing CSP policy found

FIX

No enforcing CSP policy found

No Content-Security-Policy header found

CSP is the most effective defense against XSS attacks. Add a Content-Security-Policy header to restrict resource loading.

Expected: default-src 'self'

CSP is the most effective defense against XSS attacks. Add a Content-Security-Policy header to restrict resource loading.

Expected: default-src 'self'

Why this matters

Without a CSP, a single XSS bug can exfiltrate everything users type — credentials, payment data, session tokens.

Learn more ▾

Content-Security-Policy is the browser-enforced firewall against XSS. With a strict CSP, a script injection that would otherwise steal session cookies is silently blocked. Without it, your only defense is hoping every input on every form is escaped correctly forever. Start in Report-Only mode, fix violations, then graduate to enforcing.

Source: OWASP / MDN

F

Bot Challenge Detection

Action

Scan was blocked by PerimeterX / HUMAN -- the rest of this report does NOT reflect the real site

FIX

Scan was blocked by PerimeterX / HUMAN -- the rest of this report does NOT reflect the real site

Scan returned a PerimeterX / HUMAN bot-protection interstitial, not the actual page

The HTML captured by the scanner is a `PerimeterX / HUMAN` 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: px-captcha in HTML -- HUMAN/PerimeterX 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 301, title: Skyscanner

F

Empty Page Detection

Action

1 empty-page signal(s) detected -- page may be a placeholder or have content-rendering bugs

FIX

1 empty-page signal(s) detected -- page may be a placeholder or have content-rendering bugs

Page body has only 48 chars of text -- likely empty / placeholder

After HTML stripping, the page body contains 48 characters of text content. Below 200 chars almost always means: (1) the page is a placeholder that was never filled in, (2) JavaScript was supposed to render content but failed, (3) the page is a redirect / interstitial / wrapper that should have a real status code other than 200, or (4) it's a legitimately small page like a single-form login (in which case this finding is a false positive that confirms 'minimal content' is intentional). Review the page in a browser. If content is missing, the most common root cause is a JS-rendering pipeline that needs prerendering or server-side rendering for crawlers / scanners to capture content.

Got: 48 chars

D

Permissions-Policy

Action

No header set

FIX

No header set

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=()

B

WAF / Bot Protection

No WAF detected via response headers

REVIEW

No WAF detected via response headers

No WAF detected

Response headers don't match any known WAF or bot-management product. Sites exposed to abuse (login, signup, payment) typically benefit from a WAF such as Cloudflare, Akamai, AWS WAF, or Imperva.

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

1 inline style attribute(s) detected

REVIEW

1 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. 1 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.

C

Permissions-Policy Granularity

Action

No Permissions-Policy header set -- powerful features (camera / microphone / geolocation / payment / USB) default to allow-on-same-origin

REVIEW

No Permissions-Policy header set -- powerful features (camera / microphone / geolocation / payment / USB) default to allow-on-same-origin

Permissions-Policy header not set -- features default to allow-on-same-origin

Without a `Permissions-Policy` (or legacy `Feature-Policy`) header, every powerful browser feature defaults to its spec default policy (typically `self`). A third-party iframe injected via XSS or a misconfigured embed can still request access to the user's camera, microphone, geolocation, payment APIs, USB devices, etc. Explicitly deny features the page doesn't need: ``` Permissions-Policy: camera=(), microphone=(), geolocation=(), payment=(), usb=(), accelerometer=(), gyroscope=() ``` Features the page legitimately uses can stay enabled with `feature=(self)`.

Got: header absent

B

Referrer-Policy Strictness

Referrer-Policy header not set -- browser default applies (modern: strict-origin-when-cross-origin; legacy browsers: no-referrer-when-downgrade)

REVIEW

Referrer-Policy header not set -- browser default applies (modern: strict-origin-when-cross-origin; legacy browsers: no-referrer-when-downgrade)

Referrer-Policy header not set -- browser default applies

Without an explicit `Referrer-Policy` header, the browser falls back to its default policy. Modern browsers (Chrome 85+, Firefox 87+, Safari 15+) default to `strict-origin-when-cross-origin`, which is privacy-safe. Legacy browsers default to the leaky `no-referrer-when-downgrade`, which sends the full URL (including path + query) on cross-origin HTTPS-to-HTTPS requests. Set an explicit header to ensure consistent behavior: ``` Referrer-Policy: strict-origin-when-cross-origin ``` This matches the modern browser default and is privacy-safe without breaking referrer-based same-origin analytics.

Got: header absent

C

Source Map Exposure

Action

1 publicly-accessible source map(s) -- full source code leaked

REVIEW

1 publicly-accessible source map(s) -- full source code leaked

1 publicly-accessible JavaScript source map(s)

Source maps (.js.map files) reveal the original source code -- variable names, comments, file structure, and sometimes secrets that were stripped from the bundled output. They're shipped to production by mistake almost universally; the standard fix is a build-tool config flag (Webpack: `devtool: false` or `'hidden-source-map'`; Vite: `build.sourcemap: false`; Next.js: `productionBrowserSourceMaps: false`). Once removed, audit your CDN/edge cache to evict any previously-cached .map URLs. Sample accessible URLs: https://skyscanner.net/static/js/main.80db1e99.js.map.

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 1.2, 7 checks passed

PASS

TLS 1.2, 7 checks passed

TLS 1.2 is used

Got: TLS 1.2

TLS 1.3 is not negotiated

TLS 1.3 offers improved performance and security. Consider enabling it.

Got: TLS 1.2

Strong cipher suite is used

Got: TLS_ECDHE_ECDSA_WITH_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 60 days)

Got: 2026-07-10T08:16:39Z

Certificate chain has 2 certificates

Certificate uses modern signature algorithm

Got: ECDSA-SHA384

Certificate covers 1 domain(s)

Got: skyscanner.net

Certificate is issued by a trusted CA

Got: CN=E8,O=Let's Encrypt,C=US

TLS 1.3 offers improved performance and security. Consider enabling it.

Why this matters

TLS 1.3 not in use — connection falls back to 1.2 and pays the extra round-trip.

Learn more ▾

Most clients prefer TLS 1.3 if both sides support it. If your server has TLS 1.3 enabled but it's not being negotiated, check for a downgrade-attack mitigation issue or a misconfigured cipher list. nginx ≥ 1.13.0 and OpenSSL ≥ 1.1.1 support TLS 1.3.

Source: RFC 8446 / Mozilla SSL Config

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 1.2

Cipher Suite

TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256

HTTP Version

HTTP/1.1

Certificate Chain

Leaf Certificate

Subject CN=skyscanner.netIssuer CN=E8,O=Let's Encrypt,C=USValid 2026-04-11T08:16:40Z → 2026-07-10T08:16:39ZExpires in 60 days SANs skyscanner.netSignature ECDSA-SHA384Serial 69017c95ffef4cd6ff221ee7ffa957f7ef1

Intermediate (CA Certificate)

Subject CN=E8,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 63959363c24e7082715918bfc3d7ed56

A+

Cookie Security

No cookies set — no cookie security risks

PASS

No cookies set — no cookie security risks

No cookies detected — no cookie security risks to report.

A+

Cookie Hygiene

No cookies set -- cookie-hygiene check is N/A

PASS

No cookies set -- cookie-hygiene check is N/A

No cookies set

A+

Cross-Origin Tab Safety

No new-tab links found -- no tabnabbing surface

PASS

No new-tab links found -- no tabnabbing surface

No new-tab links present

A+

Trusted Types (XSS Sink Hardening)

No CSP header -- Trusted Types check is N/A

PASS

No CSP header -- Trusted Types check is N/A

No CSP header found -- Trusted Types check is N/A

A+

Soft-404 Detection

HTTP status is non-2xx -- soft-404 check is N/A

PASS

HTTP status is non-2xx -- soft-404 check is N/A

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+

Subresource Integrity Adoption

Page has no third-party scripts or stylesheets -- SRI not applicable

PASS

Page has no third-party scripts or stylesheets -- SRI not applicable

No third-party scripts or stylesheets to protect with SRI

A+

CORS Depth

No CORS response headers -- the resource is same-origin-only by browser default

PASS

No CORS response headers -- the resource is same-origin-only by browser default

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+

Subresource Integrity

No external resources

PASS

No external resources

No external resources to protect

SRI Coverage No external resources — SRI not applicable

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

Email Security

DMARC: reject, SPF: -all, DKIM

PASS

DMARC: reject, SPF: -all, DKIM

DMARC policy is reject — strongest protection

SPF ends in -all (hard fail) — strongest setting

DKIM configured (selectors: smtpapi, k2, selector1, s1, s2)

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; rua=mailto:dmarc_agg@skyscanner.net; ruf=mailto:dmarc_fr@skyscanner.net; fo=1; pct=100;

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.

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, preload)

HSTS preload enabled