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Security report for claws-mail.org

Technology · Spain

Medium risk. 6 critical or high findings in Security headers, GDPR outside view and 1 other check.

Security score

56/100

Risk levelMedium

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

Claws Mail is an established open source email client project founded in 2006, offering a lightweight, fast, and user-friendly email and news reading experience based on GTK+. The website provides detailed descriptions of the software's features, plugins, and user documentation, targeting both new and experienced users seeking a robust email client alternative. Technically, the site is simple with basic JavaScript and CSS, hosted by Gandi SAS, and shows moderate performance and basic mobile optimization. Security posture is moderate with domain transfer protection but lacks DNSSEC and security headers. No privacy or cookie policies are published, and no contact or incident response information is provided, which limits compliance and transparency. Overall, the site is trustworthy and legitimate but could improve in security and privacy compliance.

Scanned

NIS2 and GDPR posture

GDPR outside view
50/ 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

6 findings rated critical or high. Fix these first.

  1. 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"

    • 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';…
  2. GDPR outside view

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

    • 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

    • 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

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

Keep watching claws-mail.org

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.

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Recommended

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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
72
Security headers
30
Email security
70
DNS health
75
Network security
40
GDPR outside view
50
Average
56

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 claws-mail.org, from OffSeq Breach.

Total records
2
Employees
0
Customers
2
Third parties
0
Weak passwords
50%

1 subdomain affected

See the 10 newest leaked credentials

A one-off add-on to this report that lists the most recent identifier and password pairs OffSeq Breach holds for claws-mail.org.

Select it in the checkout above.

Breach keeps ingesting new leaks, so these numbers can grow between scans.

Technical appendix

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

Business context

Business profile

The project operates in the technology sector as an open source software provider with a niche focus on email client users. Its business model revolves around GPL licensing and community-driven development with plugin extensibility. The domain's long registration history and consistent WHOIS data support its credibility. The absence of commercial advertising or tracking indicates a community or volunteer-driven approach rather than a revenue-focused model. The target audience includes individual users and possibly small organizations seeking a lightweight email client. The project maintains a presence with bug tracking, developer resources, and internationalization status, indicating active development and community engagement.

Security posture

The website demonstrates a basic security posture with HTTPS implied but no explicit security headers detected in the provided data. The domain is protected against unauthorized transfers, but DNSSEC is not enabled, which is a recommended improvement. No vulnerability disclosure or incident response information is published, which could hinder timely security communication. The lack of privacy and cookie policies also indicates potential compliance gaps with GDPR and other data protection regulations. No exposed sensitive data or vulnerable libraries were detected. Overall, the security maturity is moderate but could benefit from enhanced policies, headers, and transparency.

Recommendations

  1. Enable DNSSEC on the domain to enhance DNS security and prevent spoofing.
  2. Publish comprehensive privacy and cookie policies to improve GDPR compliance and user trust.
  3. Implement standard security headers such as Content-Security-Policy, X-Frame-Options, and Strict-Transport-Security.
  4. Add clear contact information and incident response details, including security contact emails.
  5. Consider creating and publishing a security.txt file to facilitate vulnerability reporting and improve security culture.
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Description
Claws Mail is an email client and news reader based on GTK+, featuring quick response, a graceful and sophisticated interface, easy configuration, abundant features, extensibility, robustness, and stability. It supports standard MH format for message management and offers import/export compatibility with other email clients. Additional functionalities like RSS aggregator, calendar, and laptop LED handling are provided via plugins. Distributed under GPL.
Key services
Email client software, News reader, Plugins for extended functionality
Content quality
good
Branding
consistent

Technology

Stack
GTK+, JavaScript
Performance
moderate
Mobile
basic
Accessibility
basic
SEO
basic

Security

Observed score
50/100
Good practices seen
  • Domain status clientTransferProhibited set

Analytics and tracking

Tracking level
minimal
Privacy practices
poor

Advertising

Transparency
poor

Site quality

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

Key observations

  1. Website is accessible with full content and no blocking detected.
  2. No privacy, cookie, or terms of service policies found on the site.
  3. No contact emails, phone numbers, or physical addresses explicitly provided.
  4. No security or incident response policies published.
  5. Website uses basic JavaScript and CSS with no advanced frameworks detected.
  6. No analytics or advertising scripts detected.
  7. Content is focused on open source email client software with technical and user documentation links.
  8. WHOIS data indicates a well-established domain with consistent registration details.
Technical notes

Notes

The website uses a simple technology stack primarily based on GTK+ for the software and basic JavaScript for UI interactions. No advanced frameworks or CMS platforms are detected. Hosting is provided by Gandi SAS, a reputable registrar and hosting provider. The site performance is moderate with basic mobile optimization and accessibility features. SEO optimization is basic with minimal meta tags and no structured data or Open Graph tags found. The site structure is clear and navigable but could benefit from modernization and enhanced technical SEO practices. No analytics or tracking scripts are present, indicating minimal data collection.
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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