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Security report for duelonline.cz

Ace IT s.r.o. · Technology · Czech Republic

High risk. 10 critical or high findings in GDPR outside view, Security headers and 2 other checks.

Security score

45/100

Risk levelHigh

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

DuelOnline.cz is a Czech Republic-based online accounting portal focused on providing cloud-based access to the DUEL economic system. The website targets accounting professionals, businesses, and accounting firms seeking secure, remote, and integrated accounting solutions. The business model revolves around SaaS delivery of accounting, payroll, inventory, and retail sales management services. The company Ace IT s.r.o. appears as the parent entity, with partnerships with major technology providers such as HP, Dell, Cisco, Microsoft, and Debian, enhancing its market credibility. Technically, the website employs a traditional web stack with jQuery 1.6.1, jQuery UI, and Google Analytics for tracking. It integrates virtualization technologies and cloud infrastructure based on Microsoft and Linux platforms. However, the site shows signs of aging technology and lacks modern security headers and HTTPS confirmation, which impacts its security posture. Mobile optimization and accessibility are basic, and no CMS or hosting provider details are evident. From a security perspective, the site demonstrates some best practices like data backup and physical server security but lacks visible HTTPS enforcement, security headers, and formal privacy or cookie policies. The absence of WHOIS data reduces domain trustworthiness and raises concerns about domain registration legitimacy. No vulnerability disclosures or incident response contacts are provided, limiting transparency. Overall, DuelOnline.cz is a functional and professional business site with moderate technical maturity and security posture. Strategic improvements in security, privacy compliance, and technology modernization are recommended to enhance trust and resilience.

Scanned

NIS2 and GDPR posture

GDPR outside view
10/ 100 · Critical
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

10 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 Privacy Policy found

      GDPR requires a clear and accessible privacy policy

      What to do: Add a comprehensive privacy policy page and link to it prominently

  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 Strict-Transport-Security header

      Forces HTTPS connections

      What to do: Add "Strict-Transport-Security: max-age=31536000; includeSubDomains; preload"

      • CWE-319
      • OWASP A04:2025
      • ASVS V3.4.1
    • High

      Missing X-Frame-Options header

      Prevents clickjacking attacks

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

    • 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';…

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

Keep watching duelonline.cz

This scan found 25 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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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
62
Security headers
20
Email security
85
DNS health
75
Network security
20
GDPR outside view
10
Average
45

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

Breach exposure

Leaked credentials and lookalike domains from OffSeq Breach. The counts are free; the detailed lists are paid add-ons.

Dark web exposure

Add-on

Leaked records that mention duelonline.cz, from OffSeq Breach.

No leaked records found

Breach holds no records for duelonline.cz right now. New leaks arrive continuously, so monitoring on Breach alerts you if that changes.

Monitor on Breach (opens in a new tab)

Technical appendix

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

Business context

Business profile

DuelOnline.cz occupies a niche in the Czech accounting software market, leveraging cloud and virtualization technologies to offer remote access to the DUEL economic system. Its competitive advantage lies in combining accounting expertise with IT infrastructure know-how, supported by partnerships with leading hardware and software vendors. The business model is subscription-based SaaS targeting SMEs and accounting firms needing secure, centralized data access without investing in physical servers. The presence of testimonials and partner logos supports credibility. However, the lack of transparent privacy and security policies and missing WHOIS data may hinder trust among privacy-conscious customers. Growth potential exists through enhanced compliance and modernization.

Security posture

The website's security maturity is moderate but incomplete. While it mentions physical and software security measures and backup systems, the absence of HTTPS confirmation and security headers is a significant gap. The use of an outdated jQuery version introduces potential vulnerabilities. No formal privacy, cookie, or incident response policies are published, which is a compliance risk under GDPR and related regulations. The missing WHOIS data further reduces trust in domain legitimacy. Overall, the site needs to implement modern security best practices, including HTTPS, CSP, HSTS, and publish clear privacy and incident response information to improve its security posture and compliance.

Recommendations

  1. Implement HTTPS with a valid SSL/TLS certificate and enforce secure connections site-wide.
  2. Add standard security headers such as Content-Security-Policy, Strict-Transport-Security, X-Frame-Options, and X-XSS-Protection.
  3. Publish comprehensive privacy and cookie policies with GDPR compliance details and implement a cookie consent mechanism.
  4. Update JavaScript libraries to supported, secure versions to mitigate known vulnerabilities.
  5. Verify and publish domain WHOIS information to improve trust and legitimacy perception.
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
Ace IT s.r.o.
Description
Moderní účetnictví online. Ekonomický systém DUEL Účetnictví, Daňová evidence, Mzdy, Sklady, Malobchodní prodej, Majetek, Kancelář, E-Shop
Key services
Online accounting, Economic system DUEL, Tax evidence, Payroll, Inventory management, Retail sales, Asset management, Office and e-shop integration
Content quality
good
Branding
consistent

Technology

Stack
jQuery 1.6.1, jQuery UI, Google Analytics, CSS, HTML5/XHTML, Linux KVM virtualization, Debian, HP and Dell hardware
Platforms
Windows Server, Linux
Performance
moderate
Mobile
basic
Accessibility
basic
SEO
good

Security

Observed score
60/100
Good practices seen
  • Use of virtualization and mirroring
  • Soft and physical server security
  • Backup and data recovery system

Analytics and tracking

Services
Google Analytics
Tracking level
moderate
Privacy practices
poor

Advertising

Transparency
basic

Site quality

Design
good
User experience
good
Content relevance
good
Navigation
good
Professionalism
good
Trustworthiness
moderate

Key observations

  1. Website is accessible and not blocked by WAF or security mechanisms.
  2. WHOIS data is missing, which is unusual and reduces domain trust.
  3. No privacy, cookie, or terms of service policies found on the site.
  4. Contact information is present and clearly displayed in the footer.
  5. Website uses older jQuery version (1.6.1) which may have security risks.
  6. Google Analytics is used for tracking without visible cookie consent mechanism.
  7. Site content is business-focused, targeting accounting software users.
  8. Partner logos indicate collaboration with reputable technology companies.
  9. No forms detected on the homepage HTML provided.
  10. No social media links found in the HTML content.
Technical notes

Notes

The website uses a legacy technology stack with jQuery 1.6.1 and jQuery UI, which are outdated and may pose security risks. Google Analytics is integrated for user tracking but without visible cookie consent. The site relies on virtualization technologies including KVM and Microsoft Hyper-V, and hardware from HP and Dell, indicating a hybrid infrastructure approach. Performance is moderate with basic mobile optimization and accessibility. No CMS or hosting provider details are evident, suggesting a custom or self-managed environment. SEO is supported by meta tags and structured navigation. Modernization opportunities include updating libraries, improving mobile responsiveness, and enhancing security configurations.
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

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