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Security report for o2online.de

o2 · Telecommunications · Germany

High risk. 16 critical or high findings in Network security, Security headers and 2 other checks.

Security score

49/100

Risk levelHigh

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

The website www.o2online.de represents a major German telecommunications provider offering a wide range of mobile tariffs, smartphones, home internet services, and bundled offers. The site targets both private and business customers in Germany, providing comprehensive product information and a professional user experience. The brand is consistent and well-established, supported by Telefónica Germany GmbH & Co. OHG as the parent company. The digital infrastructure leverages modern web technologies including JavaScript ES modules, a proprietary CMS, and consent management tools, ensuring a responsive and accessible platform. Security posture is strong with HTTPS enforcement and consent mechanisms, though explicit security headers should be verified. Privacy policies and cookie consent are present and GDPR compliant. WHOIS data is limited due to DENIC restrictions but aligns with legitimate ownership. Overall, the site is professional, trustworthy, and well-positioned in the telecommunications market.

Scanned

This is an earlier scan of o2online.de. View the latest report

NIS2 and GDPR posture

GDPR outside view
73/ 100 · Medium
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

16 findings rated critical or high. Fix these first.

  1. Network security

    Services reachable from the internet are the first thing attackers probe. Anything open that does not need to be should be closed.

    • Critical

      Critical Service Exposed: Telnet

      Port 23 (Telnet) is publicly accessible - Telnet - Unencrypted remote access

      What to do: Immediately restrict access to Telnet using firewall or VPN

      • NIS2 21(2)(e)
      • IR 2024/2690 6.7.2(f): Implementing Regulation (EU) 2024/2690, Annex point 6.7.2(f): Network security
      • NIST CM-7: NIST SP 800-53 Rev. 5 CM-7: Least Functionality
      • NIST SC-7: NIST SP 800-53 Rev. 5 SC-7: Boundary Protection
    • Critical

      Critical Service Exposed: SMB

      Port 445 (SMB) is publicly accessible - SMB - Windows file sharing, high risk

      What to do: Immediately restrict access to SMB using firewall or VPN

      • NIS2 21(2)(e)
      • IR 2024/2690 6.7.2(f): Implementing Regulation (EU) 2024/2690, Annex point 6.7.2(f): Network security
      • NIST CM-7: NIST SP 800-53 Rev. 5 CM-7: Least Functionality
      • NIST SC-7: NIST SP 800-53 Rev. 5 SC-7: Boundary Protection
    • Critical

      Critical Service Exposed: MSSQL

      Port 1433 (MSSQL) is publicly accessible - MSSQL - Database server

      What to do: Immediately restrict access to MSSQL using firewall or VPN

      • NIS2 21(2)(e)
      • IR 2024/2690 6.7.2(f): Implementing Regulation (EU) 2024/2690, Annex point 6.7.2(f): Network security
      • NIST CM-7: NIST SP 800-53 Rev. 5 CM-7: Least Functionality
      • NIST SC-7: NIST SP 800-53 Rev. 5 SC-7: Boundary Protection
    • Critical

      Critical Service Exposed: Oracle

      Port 1521 (Oracle) is publicly accessible - Oracle - Database server

      What to do: Immediately restrict access to Oracle using firewall or VPN

      • NIS2 21(2)(e)
      • IR 2024/2690 6.7.2(f): Implementing Regulation (EU) 2024/2690, Annex point 6.7.2(f): Network security
      • NIST CM-7: NIST SP 800-53 Rev. 5 CM-7: Least Functionality
      • NIST SC-7: NIST SP 800-53 Rev. 5 SC-7: Boundary Protection
    • Critical

      Critical Service Exposed: MySQL

      Port 3306 (MySQL) is publicly accessible - MySQL - Database server

      What to do: Immediately restrict access to MySQL using firewall or VPN

      • NIS2 21(2)(e)
      • IR 2024/2690 6.7.2(f): Implementing Regulation (EU) 2024/2690, Annex point 6.7.2(f): Network security
      • NIST CM-7: NIST SP 800-53 Rev. 5 CM-7: Least Functionality
      • NIST SC-7: NIST SP 800-53 Rev. 5 SC-7: Boundary Protection

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

Keep watching o2online.de

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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
75
Security headers
60
Email security
60
DNS health
65
Network security
0
GDPR outside view
73
Average
56
After the cap
49

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 · found on this site
  • 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

O2online.de operates as a large telecommunications entity in Germany, offering mobile and internet services with a focus on competitive tariffs and device sales. The business model includes direct consumer sales, bundled offers, and value-added services like entertainment and insurance. The company benefits from a strong parent brand, Telefónica Germany, and maintains a partner ecosystem including business-focused domains. The website's content and structure support customer acquisition and retention through clear navigation and targeted offers. Marketing and personalization tools like Trbo enhance user engagement. The company targets a broad customer base including young users, families, and business clients, indicating a diversified revenue stream and growth potential.

Security posture

The website demonstrates a mature security posture with HTTPS enforced and integration of a consent management platform (Usercentrics) for GDPR compliance. No exposed sensitive data or vulnerable libraries were detected in the HTML content. The use of secure login layers and modern JavaScript modules indicates good security practices. However, explicit presence of security headers such as Content-Security-Policy, X-Frame-Options, and X-Content-Type-Options was not confirmed and should be audited. Incident response and vulnerability disclosure information are not publicly visible, suggesting room for improvement in transparency and readiness. Overall, the security posture is strong but could benefit from enhanced header policies and published security policies.

Recommendations

  1. Conduct a thorough audit to ensure all recommended security headers (CSP, X-Frame-Options, X-Content-Type-Options) are implemented.
  2. Publish a clear vulnerability disclosure policy and security.txt file to improve transparency and encourage responsible reporting.
  3. Enhance visibility of incident response contacts to facilitate timely communication of security issues.
  4. Regularly review third-party scripts and libraries for vulnerabilities and update them promptly.
  5. Maintain and update privacy and cookie policies to reflect evolving regulations and best practices.
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
o2
Description
Dein Mobilfunkanbieter für günstige Handytarife, Top-Smartphones, Internet mobil & zu Hause. o2 Angebote entdecken.
Key services
Mobile phone tariffs, Smartphones and devices, Home internet (DSL, cable, fiber, LTE/5G), Bundled offers (mobile + internet), Entertainment services (TV, streaming), Insurance and online protection
Content quality
excellent
Branding
consistent

Technology

Stack
JavaScript ES modules, IntersectionObserver API, Usercentrics CMP for consent management, Trbo for personalization and ad spaces, Telefonica library components, JSON-LD structured data
Frameworks
OCCL (Telefonica's own component library)
Platforms
Web (desktop and mobile optimized)
Performance
moderate
Mobile
excellent
Accessibility
good
SEO
good

Security

Observed score
85/100
Good practices seen
  • HTTPS enforced
  • Consent management via Usercentrics
  • No exposed sensitive data in HTML
  • Secure login layers
  • Use of modern JS modules

Analytics and tracking

Services
Google Tag Manager
Tracking level
moderate
Privacy practices
good

Advertising

Ad networks
Trbo
Tracking pixels
Usercentrics
Marketing tools
Usercentrics CMP, Trbo personalization
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 detected.
  2. Strong brand presence with consistent branding and professional design.
  3. Comprehensive product and service offerings clearly presented.
  4. Use of modern web technologies and consent management tools.
  5. No exposed sensitive data or obvious security vulnerabilities in HTML.
  6. WHOIS data limited due to DENIC policy but domain appears legitimate.
  7. Multiple external domains related to official partners and service providers.
  8. Good privacy and cookie policy presence with consent mechanisms.
  9. No explicit contact emails found in HTML; phone contact clearly provided.
  10. No security.txt or vulnerability disclosure policy detected.
Technical notes

Notes

The website uses a modern technology stack including ES modules, IntersectionObserver for lazy loading, and a proprietary CMS from Telefónica. It integrates third-party services such as Usercentrics for consent management and Trbo for personalization and advertising. The site is mobile-optimized with responsive design and accessibility features. Performance is moderate, with asynchronous loading of scripts and preconnect/dns-prefetch hints to improve speed. The use of JSON-LD structured data and Open Graph tags supports SEO and social media sharing. Hosting provider details are not explicit but likely managed by Telefónica or a trusted partner. Overall, the technical infrastructure is robust and supports a high-quality user experience.
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. 49/100High44 findingsView report
  2. 49/100High41 findingsView report
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