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https://idnes.cz

Security

· 12 checks — HTTP headers, CSP, TLS handshake, and cookie hygiene rolled into one auditable list.
SCORE
66
GRADE
D
FIX
5
REVIEW
2
PASS
5
INFO
0
Checks
12
5 PASS 2 REVIEW 5 FIX
D
Security Headers
Action
4 of 10 headers properly configured
FIX
4 of 10 headers properly configured
Warning::
HSTS max-age is too short (15552000s, should be ≥ 31536000s)
A short max-age leaves a window for downgrade attacks. Set max-age to at least 31536000 (1 year).
Got: max-age=15552000 Expected: max-age=31536000; includeSubDomains
Info::
X-Content-Type-Options is properly configured
Got: nosniff
Info::
X-Frame-Options is properly configured
Got: SAMEORIGIN
Info::
Referrer-Policy is properly configured
Got: no-referrer-when-downgrade
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=()
Critical::
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'
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
Warning::
X-Powered-By header reveals technology stack
This header discloses server technology (e.g. Express, PHP), helping attackers target known vulnerabilities. Remove it.
Got: iDNES iweb49
Info::
Server header is not present

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

A short max-age leaves a window for downgrade attacks. Set max-age to at least 31536000 (1 year).

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

Short HSTS max-age leaves a downgrade-attack window every time the cache expires — set ≥ 1 year.

Learn more ▾

max-age below 31536000 (1 year) is below industry recommendation. The browser forgets the HSTS policy and re-exposes first-visit downgrade attacks. Set to 63072000 (2 years) and add `includeSubDomains; preload` to qualify for the HSTS preload list.

Source: RFC 6797 / hstspreload.org

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

This header discloses server technology (e.g. Express, PHP), helping attackers target known vulnerabilities. Remove it.

Why this matters

X-Powered-By: PHP/7.4.3 advertises your stack to attackers — disable it.

Learn more ▾

X-Powered-By and similar headers (X-AspNet-Version, X-Runtime) tell attackers which versions to target. Disable in your server/framework config: PHP `expose_php=Off`, ASP.NET `<httpRuntime enableVersionHeader="false">`, Express `app.disable('x-powered-by')`.

Source: OWASP

F
Content Security Policy
Action
No enforcing CSP policy found
FIX
No enforcing CSP policy found
Critical::
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
Subresource Integrity
Action
0 of 29 external resources have SRI
FIX
0 of 29 external resources have SRI
Warning::
External script from www.googletagmanager.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://www.googletagmanager.com/gtag/js?id=G-N7BYSDJ0DC&cx=c&gtm=4e64h1
Warning::
External script from privacy.1gr.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://privacy.1gr.cz/9a8e2159-3781-4da1-9590-fbf86806f86e/loader.js?target_type=notice&target=G2CLdMkM
Warning::
External script from www.googletagmanager.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: //www.googletagmanager.com/gtm.js?id=GTM-WD22KH
Warning::
External script from spir.hit.gemius.pl lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://spir.hit.gemius.pl/xgemius.js
Warning::
External script from cdn.cpex.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://cdn.cpex.cz/package/cpex-package.min.js
Warning::
External script from delivery.r2b2.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://delivery.r2b2.cz/hb/mafra/homepage.idnes.cz_desktop
Warning::
External script from 1gr.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://1gr.cz/js/uni/uni.js?rr=1774003235
Warning::
External script from 1gr.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://1gr.cz/js/cmp/cookiewallCMP.js
Warning::
External script from accounts.google.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://accounts.google.com/gsi/client
Warning::
External script from www.idnes.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: //www.idnes.cz/_servix/webid.aspx
Warning::
External script from pagead2.googlesyndication.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://pagead2.googlesyndication.com/tag/js/gpt.js
Warning::
External script from privacy.1gr.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://privacy.1gr.cz/sdk/22ecd6bfac93de604efec0b75b2c796ee1675f92/modern/sdk.22ecd6bfac93de604efec0b75b2c796ee1675f92.js
Warning::
External script from cdn.cpex.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://cdn.cpex.cz/settings/production/mafra.js
Warning::
External script from cdn.cpex.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://cdn.cpex.cz/settings/production/mafra/idnes.cz.js
Warning::
External script from cdn.cpex.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://cdn.cpex.cz/hb/prebid/prebid.min.js
Warning::
External script from ssp.seznam.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: //ssp.seznam.cz/static/js/ssp.js
Warning::
External link from accounts.google.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://accounts.google.com/gsi/style
Warning::
External script from pagead2.googlesyndication.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://pagead2.googlesyndication.com/pagead/managed/js/gpt/m202604170101/pubads_impl.js?cb=31097946
Warning::
External script from delivery.r2b2.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: //delivery.r2b2.cz/js/7.99.0/online/public/bundle.ddbf08647995741ec209.js
Warning::
External script from h.seznam.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: //h.seznam.cz/js/dot-small.js
Warning::
External script from a.1gr.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://a.1gr.cz/mafra/tserver/ball/random=2957051/site=idnes_cz/viewid=3612890/b1/size=970x310,750x100,728x90,970x250,970x210/area=wallpaper/fcid=52806
Warning::
External script from delivery.r2b2.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: //delivery.r2b2.cz/get/homepage.idnes.cz/generic/hypertext_2?pbid=hypertext_2
Warning::
External script from delivery.r2b2.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: //delivery.r2b2.cz/get/homepage.idnes.cz/generic/hypertext_5?pbid=hypertext_5
Warning::
External script from delivery.r2b2.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: //delivery.r2b2.cz/get/homepage.idnes.cz/generic/hypertext_4?pbid=hypertext_4
Warning::
External script from delivery.r2b2.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: //delivery.r2b2.cz/get/homepage.idnes.cz/generic/hypertext_3?pbid=hypertext_3
Warning::
External script from 1gr.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://1gr.cz/js/sph/mereni.js?rr=1717074100441
Warning::
External script from 1gr.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://1gr.cz/js/uni/paticka.js?rr=1776765780
Warning::
External script from 1gr.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://1gr.cz/js/sph/2025.js?rr=1775651079
Warning::
External script from 1gr.cz lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://1gr.cz/js/zpravy/recombee-2024.js?rr=1744616587
SRI Coverage 0 / 29 of external resources have integrity hashes
TagDomainIntegrity
<script>www.googletagmanager.com✗ Missing
<script>privacy.1gr.cz✗ Missing
<script>www.googletagmanager.com✗ Missing
<script>spir.hit.gemius.pl✗ Missing
<script>cdn.cpex.cz✗ Missing
<script>delivery.r2b2.cz✗ Missing
<script>1gr.cz✗ Missing
<script>1gr.cz✗ Missing
<script>accounts.google.com✗ Missing
<script>www.idnes.cz✗ Missing
<script>pagead2.googlesyndication.com✗ Missing
<script>privacy.1gr.cz✗ Missing
<script>cdn.cpex.cz✗ Missing
<script>cdn.cpex.cz✗ Missing
<script>cdn.cpex.cz✗ Missing
<script>ssp.seznam.cz✗ Missing
<link>accounts.google.com✗ Missing
<script>pagead2.googlesyndication.com✗ Missing
<script>delivery.r2b2.cz✗ Missing
<script>h.seznam.cz✗ Missing
<script>a.1gr.cz✗ Missing
<script>delivery.r2b2.cz✗ Missing
<script>delivery.r2b2.cz✗ Missing
<script>delivery.r2b2.cz✗ Missing
<script>delivery.r2b2.cz✗ Missing
<script>1gr.cz✗ Missing
<script>1gr.cz✗ Missing
<script>1gr.cz✗ Missing
<script>1gr.cz✗ Missing
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
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
B
Transport Security
HTTP/3, HSTS, and TLS version analysis
REVIEW
HTTP/3, HSTS, and TLS version analysis
Info::
HTTP/3 (QUIC) not advertised
HTTP/3 eliminates head-of-line blocking. If your CDN supports it, consider enabling it.
Warning::
HSTS max-age is short: 180 days
HSTS max-age should be at least 1 year (31536000 seconds).
Got: max-age=15552000 (expected 31536000)
Info::
HSTS missing includeSubDomains
Without includeSubDomains, HSTS only protects the exact domain.
Info::
TLS 1.3 in use (fastest handshake, 1-RTT)
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_256_GCM_SHA384
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 293 days)
Got: 2027-02-08T23:59:59Z
Info::
Certificate chain has 3 certificates
Info::
Certificate uses modern signature algorithm
Got: ECDSA-SHA256
Info::
Certificate covers 2 domain(s)
Got: *.idnes.cz, idnes.cz
Info::
Certificate is issued by a trusted CA
Got: CN=Sectigo Public Server Authentication CA DV E36,O=Sectigo Limited,C=GB

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_256_GCM_SHA384
HTTP Version
HTTP/1.1

Certificate Chain

Leaf Certificate
Subject CN=*.idnes.czIssuer CN=Sectigo Public Server Authentication CA DV E36,O=Sectigo Limited,C=GBValid 2026-01-13T00:00:00Z → 2027-02-08T23:59:59ZExpires in 293 days SANs *.idnes.cz, idnes.czSignature ECDSA-SHA256Serial b5bbead93ee72e36feb063198b8f4674
Intermediate (CA Certificate)
Subject CN=Sectigo Public Server Authentication CA DV E36,O=Sectigo Limited,C=GBIssuer CN=Sectigo Public Server Authentication Root E46,O=Sectigo Limited,C=GBValid 2021-03-22T00:00:00Z → 2036-03-21T23:59:59ZExpires in 3622 days Signature ECDSA-SHA384Serial 36e059ed888dd57aedd570b6727f9bda
Intermediate (CA Certificate)
Subject CN=Sectigo Public Server Authentication Root E46,O=Sectigo Limited,C=GBIssuer CN=USERTrust ECC Certification Authority,O=The USERTRUST Network,L=Jersey City,ST=New Jersey,C=USValid 2021-03-22T00:00:00Z → 2038-01-18T23:59:59ZExpires in 4290 days Signature ECDSA-SHA384Serial 1a9eafec6de8e19b5c193141b68d90dd
A
Cookie Security
2 cookies analyzed, 4 checks passed
PASS
2 cookies analyzed, 4 checks passed
Info::
Cookie '_webid' has the Secure flag
Warning::
Cookie '_webid' is missing the HttpOnly flag
Without HttpOnly, this cookie can be accessed by JavaScript, making it vulnerable to XSS-based theft.
Info::
Cookie '_webid' has SameSite=None
Info::
Cookie '_mmid' has the Secure flag
Warning::
Cookie '_mmid' is missing the HttpOnly flag
Without HttpOnly, this cookie can be accessed by JavaScript, making it vulnerable to XSS-based theft.
Info::
Cookie '_mmid' has SameSite=None
2 cookies analyzed 2 warnings
NameSecureHttpOnlySameSiteSizeIssues
_webid✓✗None40 B1
_mmid✓✗None21 B1
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: reject
PASS
DMARC: reject
Info::
DMARC policy is reject — strongest protection
DMARC
Policy reject — strongest protection Record v=DMARC1; p=reject; rua=mailto:173a1ba4@mxtoolbox.dmarc-report.com,mailto:pi1rqn5o@ag.dmarcian-eu.com,mailto:dmarc-rua@mailkit.com,mailto:dmarc+666344@smartemailing.cz; ruf=mailto:173a1ba4@forensics.dmarc-report.com; pct=10
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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