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Security report for holidu.nl

Holidu GmbH · Hospitality · Netherlands

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 leading European vacation rental search platform offering a wide selection of verified holiday homes, apartments, and villas. The website targets European travelers seeking family-friendly and pet-friendly accommodations with a strong emphasis on trust and convenience. Technically, the site employs modern web technologies including React and Tailwind CSS, with robust performance and mobile optimization. Security posture is strong with HTTPS, security headers, and secure forms, though explicit security policies and incident response contacts are not publicly disclosed. Privacy compliance is well addressed with comprehensive privacy and cookie policies and consent mechanisms. Overall, the site presents a professional, trustworthy, and user-friendly platform with a mature domain and consistent WHOIS data supporting legitimacy.

Scanned

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.nl

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

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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 is positioned as a major player in the European vacation rental market, leveraging a marketplace model aggregating listings from multiple sources. Its business model focuses on providing verified listings and a seamless booking experience. The company benefits from a broad geographic presence with sister sites in multiple countries, strong brand consistency, and trust signals such as free cancellation and app availability. The target customers are families and pet owners looking for quality vacation homes. The company appears well-established with a large user base and extensive marketing and advertising partnerships.

Security posture

The website demonstrates a mature security posture with enforced HTTPS, comprehensive security headers, and no visible vulnerabilities or exposed sensitive data. However, it lacks publicly available security policies, incident response contacts, and vulnerability disclosure mechanisms, which are recommended best practices for transparency and rapid incident handling. The use of fingerprinting technology (ThumbmarkJS) indicates advanced tracking capabilities, which should be balanced with privacy considerations. Overall, the security maturity is high but could be improved with explicit security governance disclosures.

Recommendations

  1. Publish a dedicated security policy page outlining security practices and controls.
  2. Provide clear incident response contact information for security issues.
  3. Implement and publish a vulnerability disclosure policy or security.txt file.
  4. Review and disclose data retention policies related to analytics and tracking.
  5. Enhance transparency around fingerprinting and tracking technologies to improve user trust.
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
Holidu GmbH
Description
Enorme selectie van hoogwaardige vakantiehuizen, appartementen, villa’s met geverifieerde accommodatie tegen de beste prijs. Specialist voor de mooiste vakantieregio’s in Europa.
Key services
Vacation home search, Booking platform, Verified accommodation listings
Content quality
excellent
Branding
consistent

Technology

Stack
JavaScript, React, Tailwind CSS, ThumbmarkJS fingerprinting, Google Analytics, Google Tag Manager
Frameworks
React
Platforms
Web
Performance
fast
Mobile
excellent
Accessibility
good
SEO
good

Security

Observed score
90/100
Good practices seen
  • HTTPS enforced
  • Security headers present
  • No exposed sensitive data in HTML
  • Secure forms with POST method

Analytics and tracking

Services
Google Analytics
Tracking level
extensive
Privacy practices
good

Advertising

Ad networks
Taboola, Bing Ads
Tracking pixels
Facebook Connect
Transparency
good

Site quality

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

Key observations

  1. Website is professionally designed and well-structured.
  2. Strong focus on European vacation rental market.
  3. Comprehensive cookie consent and privacy policy present.
  4. No direct contact emails or phone numbers found on homepage; contact likely via forms.
  5. Use of modern web technologies and tracking tools.
  6. No security policy or incident response info publicly available.
  7. No vulnerability disclosure or security.txt found.
  8. No suspicious or malicious indicators detected.
Technical notes

Notes

The website uses a modern and performant technology stack centered on React and Tailwind CSS, ensuring responsive and accessible user experience. It integrates multiple third-party services for analytics, advertising, and tracking, including Google Analytics, Google Tag Manager, Taboola, and Bing Ads. The site is well-optimized for SEO with proper meta tags and Open Graph data. No CMS detected, indicating a custom-built platform. Hosting provider details are not explicit but performance and security headers suggest a professional hosting environment. The site is well-maintained with no broken elements detected in the analyzed content.
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. 72/100Medium26 findingsView report
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