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Security report for holidu.dk

Holidu GmbH · Real Estate · Denmark

Medium risk. 5 critical or high findings in GDPR outside view, Security headers and 1 other check.

Security score

72/100

Risk levelMedium

0–100, higher is better. How it is calculated

Holidu GmbH operates a sophisticated online vacation rental platform specializing in European holiday homes, apartments, and summer houses. The company positions itself as a price guarantee provider with a strong focus on family-friendly and pet-friendly accommodations, offering a wide range of filters and booking options. The website is well-branded, multilingual, and targets European vacationers seeking reliable and affordable holiday rentals. Technically, the site leverages modern JavaScript frameworks like React, uses Tailwind CSS for styling, and integrates multiple analytics and advertising services including Google Analytics, Bing Ads, and Taboola. The platform demonstrates good digital maturity with responsive design and SEO optimization. Security posture is solid with HTTPS enforced and standard security headers present, though there is room for improvement in advanced headers and public security policies. Privacy compliance is strong, featuring a comprehensive privacy policy and cookie consent mechanism aligned with GDPR requirements. The absence of public WHOIS data suggests privacy protection, which is justified for this business type. Overall, Holidu presents a trustworthy and professional online presence with a high level of user experience and business credibility.

Scanned

This is an earlier scan of holidu.dk. View the latest report

NIS2 and GDPR posture

GDPR outside view
33/ 100 · High
Checks completed
7of 7

NIS2 Art. 21(2)

  1. (a) Risk analysis and security policies: Not visible from outside
  2. (b) Incident handling: One indicator
  3. (c) Business continuity, backups and crisis management: Not visible from outside
  4. (d) Supply chain security: Not visible from outside
  5. (e) Secure acquisition, development and maintenance, including vulnerability handling: Partly checked
  6. (f) Assessing the effectiveness of security measures: Not visible from outside
  7. (g) Cyber hygiene and security training: Not visible from outside
  8. (h) Cryptography and encryption: Partly checked
  9. (i) HR security, access control and asset management: One indicator
  10. (j) Multi-factor authentication and secured communications: Not visible from outside

This scan rated NIS2 with an earlier keyword method that is no longer shown; rescan for the per-article view. Risk management, continuity, supply chain, training, MFA, management oversight (Art. 20) and incident reporting (Art. 23) need internal evidence, and Guard cannot tell whether NIS2 applies to this organisation.

GDPR is indicative only, based on publicly visible signals: Articles 7, 12, 13 and 32 of Regulation (EU) 2016/679 and Article 5(3) of the ePrivacy Directive. Not a certification or legal assessment.

Priority findings

5 findings rated critical or high. Fix these first.

  1. GDPR outside view

    These are the privacy signals visitors and data protection authorities look for under GDPR.

    • Critical

      EU business without adequate privacy measures

      EU businesses are subject to strict GDPR requirements

      What to do: Implement comprehensive GDPR compliance including privacy policy, cookie consent, and data protection measures

    • High

      No Cookie Policy found

      GDPR requires clear information about cookie usage

      What to do: Add a dedicated cookie policy explaining cookie usage and purposes

    • High

      No Cookie Consent Banner found

      GDPR requires explicit consent for non-essential cookies

      What to do: Implement a cookie consent banner that appears on first visit

  2. Security headers

    Security headers are instructions your web server sends to every visitor’s browser. Missing ones leave visitors more exposed to attacks such as clickjacking and injected scripts.

    • High

      Missing Content-Security-Policy header

      Controls resources the browser is allowed to load

      What to do: Implement a Content-Security-Policy appropriate for your application

      • ASVS V3.4.3
      • OWASP Secure Headers: OWASP Secure Headers Project recommends Content-Security-Policy: default-src 'self'; form-action 'self'; base-uri 'self'; object-src 'none';…

  3. SSL/TLS

    TLS encrypts the connection and proves the site is really yours. Weak or expiring certificates trigger browser warnings and put traffic at risk.

    • High

      Weak Protocols Supported

      Server supports weak protocols: TLSv1.1

      What to do: Disable TLS 1.0, TLS 1.1, and all SSL versions

      • CWE-327
      • OWASP A04:2025
      • ASVS V12.1.1

Need hands-on remediation? Email guard@offseq.com

Keep watching holidu.dk

This scan found 18 issues across 6 checks. Monitoring re-runs those checks daily, emails you when something material changes and records each fix, so you can show progress.

Daily monitoring

Recommended

€25per month

  • TLS certificates and expiry
  • DNS records
  • SPF, DKIM and DMARC
  • Security headers
  • GDPR and NIS2 posture
  • Exposed services
  • Third-party trackers
  • Security score drift

Email alerts on material changes and an exportable JSON history of every change.

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Full report

€39.90one-time

  • The complete analysis as a PDF you can cite
  • Email delivery with an unlock code
  • Lifetime access to this report

Prices incl. 21% VAT. Secure checkout by Mollie; sold by SEQ SIA, Latvia.

Results by check

Each check with its score, findings and the evidence it collected.

How this score is calculated

The security score runs 0–100, higher is better. It is the plain average of the security checks that completed in this scan, each counted equally. A check that could not run is left out: it counts neither as a pass nor as a fail.

Counted in this score

SSL/TLS
77
Security headers
70
Email security
80
DNS health
70
Network security
100
GDPR outside view
33
Average
72

Not counted

  • NIS2 outside view: Re-weights evidence from the TLS, email, DNS, network and hygiene checks, so counting it would count that evidence twice. Shown on its own.
  • OffSeq Observations: An AI reading of the site, useful context but not reproducible evidence. Shown on its own.

Findings that cap the score at 49

Each of these is serious on its own, so while any is present the site cannot rate better than high risk, however good the other checks are.

  • The certificate is not trusted by browsers
  • The website is not served over HTTPS
  • A database, remote desktop, file-sharing or Telnet service is reachable from the internet
  • The page loads a script from a compromised source
  • The domain registration has expired
  • SPF authorises every server to send mail as the domain

Partial scans

When the site blocks Guard or most checks cannot run, the score covers only the checks that ran (usually DNS and email), is capped at 75 and is shown as partial, without a risk level.

Risk levels

  • Critical0–25
  • High26–49
  • Medium50–75
  • Low76–100

Technical appendix

Business context, site observations and technical notes gathered during the scan, and the standards behind each reference.

Business context

Business profile

Holidu holds a strong market position as a specialist vacation rental platform in Europe, leveraging a price guarantee to differentiate itself. Its business model centers on aggregating vacation rental listings and facilitating bookings, likely generating revenue through commissions or fees. The company targets families, pet owners, and travelers seeking specific amenities such as pools, sea views, and child-friendly properties. The presence of multiple localized domains indicates a broad geographic reach and a strategy to cater to diverse European markets. Trust signals such as star host badges and free cancellation policies enhance customer confidence. The partnership ecosystem includes localized country sites, and the use of major advertising and analytics platforms suggests a mature marketing approach. Growth indicators include extensive property listings and a well-maintained, content-rich website.

Security posture

The website exhibits a mature security posture with HTTPS enforced and several security headers implemented, including cache control and referrer policies. No exposed sensitive data or vulnerable libraries were detected in the HTML content. The site uses secure forms and consent mechanisms for cookies, supporting privacy compliance. However, the absence of explicit security policies, incident response contacts, or vulnerability disclosure programs indicates areas for enhancement. The lack of a security.txt file and incident response information may limit transparency in handling security incidents. Overall, the security maturity is good but could benefit from additional public documentation and advanced security headers such as Content-Security-Policy and Strict-Transport-Security.

Recommendations

  1. Implement Content-Security-Policy and Strict-Transport-Security headers to strengthen security.
  2. Publish a dedicated security policy and incident response contact information to improve transparency.
  3. Consider adding a vulnerability disclosure program or security.txt file to encourage responsible reporting.
  4. Enhance accessibility features to meet higher compliance standards and improve user experience.
  5. Maintain and regularly audit third-party scripts and tracking tools to minimize privacy risks.
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
Holidu GmbH
Description
Stort udvalg af feriehuse, ferielejligheder og sommerhuse af høj kvalitet ✔ Super indkvartering til den bedste pris, book med sikkerhed ✔ Ferieboliger med pool, havudsigt, børnevenlige eller kæledyrsvenlige ✔ Specialist i de smukkeste ferieregioner i Europa ✔
Key services
Vacation home search and booking, Price guarantee, Filters for amenities and preferences
Content quality
excellent
Branding
consistent

Technology

Stack
JavaScript, React, Tailwind CSS, Google Analytics, Google Tag Manager, Bing Ads, Taboola, ThumbmarkJS
Frameworks
React
Performance
moderate
Mobile
good
Accessibility
basic
SEO
good

Security

Observed score
85/100
Good practices seen
  • HTTPS enforced
  • No exposed sensitive data in HTML
  • Secure cookie consent mechanism

Analytics and tracking

Services
Google Analytics, Bing Ads, Taboola
Tracking level
extensive
Privacy practices
good

Advertising

Ad networks
Bing Ads, Taboola
Tracking pixels
Bing Ads, Taboola
Marketing tools
ThumbmarkJS
Transparency
good

Site quality

Design
excellent
User experience
excellent
Content relevance
excellent
Navigation
excellent
Professionalism
excellent
Trustworthiness
high

Key observations

  1. Website is fully accessible with rich content and no blocking.
  2. No WHOIS data available publicly, indicating privacy protection.
  3. Strong branding and consistent multi-language presence.
  4. Comprehensive cookie and privacy policy with consent mechanism.
  5. Use of modern web technologies and analytics/tracking tools.
  6. No direct contact emails or phone numbers found on main page.
  7. No explicit security or incident response contact information found.
  8. No vulnerability disclosure or security.txt detected.
  9. Content is safe for general audiences with no adult content.
Technical notes

Notes

The website is built using React and styled with Tailwind CSS, indicating a modern front-end technology stack. It integrates multiple third-party analytics and advertising services, including Google Analytics, Bing Ads, Taboola, and Google Tag Manager, which support extensive user tracking and marketing efforts. The site loads fonts asynchronously for performance optimization and uses preconnect hints to speed up resource loading. The presence of fingerprinting scripts like ThumbmarkJS suggests advanced user identification techniques. Performance is moderate with good mobile optimization and SEO practices. No CMS was explicitly detected, suggesting a custom or headless architecture. Hosting provider details are not evident from the HTML content. Overall, the technical infrastructure supports a scalable and user-friendly platform but requires ongoing monitoring for third-party dependencies.
Standards and sources

Reference chips under each finding point to the standard, regulation or specification the finding relates to. They are taken from the official datasets below and mapped conservatively: a finding with no defensible link shows none. NIS2 and GDPR references mark where a finding is relevant evidence, not a compliance verdict. Implementing Regulation (EU) 2024/2690 binds digital infrastructure and digital service providers; for other entities it is the most detailed public reading of the Article 21 measures. WCAG, EN 301 549, European Accessibility Act and Web Accessibility Directive references name the requirement an automated accessibility rule relates to; they are not a conformance verdict.

Retrieved 2026-10-25

Earlier scans of this domain

  1. 73/100Medium25 findingsView report
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