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Security report for viessmann.de

Viessmann · Energy · Germany

Medium risk. 5 critical or high findings in GDPR outside view, SSL/TLS and 1 other check.

Security score

53/100

Risk levelMedium

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

Viessmann is a well-established German company specializing in energy-efficient heating, cooling, and ventilation systems with a strong emphasis on renewable energy and sustainability. The website demonstrates a mature digital presence with comprehensive product and service information targeting both private customers and professional clients. Technically, the site uses modern web technologies including Adobe Experience Manager CMS, Google Tag Manager, and Usercentrics for consent management, indicating a high level of digital maturity. Security posture is solid with HTTPS enforced and consent mechanisms in place, though explicit security policies and vulnerability disclosures are absent. Overall, the site is professional, trustworthy, and aligned with industry best practices, supporting Viessmann's market position as a leader in climate and energy solutions.

Scanned

NIS2 and GDPR posture

GDPR outside view
28/ 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. 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.

    • Critical

      Unable to retrieve SSL certificate

      Could not establish secure connection to retrieve certificate information

      What to do: Check if the server is accessible and SSL/TLS is properly configured

  3. 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 X-Frame-Options header

      Prevents clickjacking attacks

      What to do: Add "X-Frame-Options: DENY" or "X-Frame-Options: SAMEORIGIN"

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

Keep watching viessmann.de

This scan found 21 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.

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

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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
0
Security headers
65
Email security
60
DNS health
65
Network security
100
GDPR outside view
28
Average
53

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

Viessmann operates in the energy sector, focusing on climate-friendly heating and energy management solutions. Their business model includes manufacturing, digital services, and consulting, serving both B2C and B2B markets. The company leverages a broad international footprint with localized domains and offers extensive product lines including heat pumps, hybrid heating, photovoltaics, and smart home integration. Awards and certifications reinforce their competitive advantage. The website's structure and content reflect a strategic focus on sustainability and innovation, supporting growth and customer engagement.

Security posture

The website exhibits a good security posture with HTTPS enforced and the use of a consent management platform to comply with privacy regulations. No critical vulnerabilities or exposed sensitive data were detected in the HTML content. However, the absence of explicit security policies, incident response contacts, and vulnerability disclosure mechanisms suggests room for improvement in transparency and incident readiness. The use of third-party scripts like Google Tag Manager and Kameleoon requires ongoing monitoring to mitigate supply chain risks. Overall, the security maturity is good but could be enhanced by publishing formal security documentation and improving header configurations.

Recommendations

  1. Publish a clear privacy policy and terms of service accessible from the homepage.
  2. Add a security policy page and incident response contact information to improve transparency.
  3. Implement and explicitly confirm security headers such as Content-Security-Policy and X-Frame-Options.
  4. Introduce a vulnerability disclosure program or security.txt file to encourage responsible reporting.
  5. Regularly audit third-party scripts and dependencies for vulnerabilities and compliance.
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
Viessmann
Description
Heiz-, Kühl- und Lüftungstechnik, die Lebensräume gestaltet und das Klima schont. Ganzheitliche Klima- und Energielösungen für alle Energieträger und Bedürfnisse mit Fokus auf Nachhaltigkeit und Effizienz.
Key services
Heating systems, Cooling systems, Ventilation systems, Energy management, Digital services (ViCare App, smart home integration), Consulting and support services
Content quality
excellent
Branding
consistent

Technology

Stack
JavaScript, Adobe Helix RUM, Google Tag Manager, Usercentrics Consent Management, Kameleoon (A/B testing and personalization)
Performance
moderate
Mobile
good
Accessibility
good
SEO
good

Security

Observed score
85/100
Good practices seen
  • HTTPS enforced
  • Consent management platform used
  • No exposed sensitive data in HTML
  • Use of asynchronous and deferred scripts

Analytics and tracking

Services
Google Analytics (via GTM)
Tracking level
moderate
Privacy practices
good

Advertising

Tracking pixels
Usercentrics, Kameleoon
Marketing tools
Usercentrics Consent Management, Kameleoon
Transparency
basic

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 navigation.
  2. Strong focus on renewable energy and climate solutions.
  3. Use of modern consent management and analytics tools.
  4. No direct contact emails or phone numbers found on homepage HTML.
  5. Multiple language alternate links indicate international presence.
  6. No explicit privacy policy or terms of service links found in provided HTML snippet.
  7. No visible security.txt or vulnerability disclosure information.
  8. Professional branding and multiple awards displayed.
Technical notes

Notes

The website is built on Adobe Experience Manager, a robust enterprise CMS, and uses modern JavaScript libraries and asynchronous loading to optimize performance. The presence of Usercentrics indicates GDPR compliance efforts. Hosting appears stable with uu.net nameservers. The site is mobile-optimized with good accessibility and SEO practices. Performance is moderate, with potential for improvement in load times and script optimization. The technical infrastructure supports a scalable and maintainable platform suitable for a large enterprise with international reach.
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. 71/100Medium30 findingsView report
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