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Security report for protonmail.com

Proton AG · Technology · Switzerland

Low risk. 4 critical or high findings in Security headers, GDPR outside view and 1 other check.

Security score

77/100

Risk levelLow

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

Proton AG operates Proton Mail, the world’s largest secure email service with over 100 million users, headquartered in Switzerland. The company offers a suite of privacy-focused services including encrypted email, calendar, cloud storage, password manager, bitcoin wallet, and VPN, all designed with privacy by default. Proton Mail is widely trusted by journalists, activists, and privacy-conscious users globally, leveraging Swiss privacy laws to protect user data. The business model is freemium, providing a free secure email service supported by paid subscription plans offering enhanced features and storage. Technically, Proton’s website employs modern web technologies including React and the Astro framework, delivering a fast, mobile-optimized, and accessible user experience. The infrastructure is robust, with domain registration managed by MarkMonitor Inc., and a CDN for content delivery. Security practices include end-to-end and zero-access encryption, open-source audited libraries, and strict domain status protections. However, DNSSEC is not enabled, which could be improved. Security posture is strong with HTTPS enforced and no visible vulnerabilities or exposed sensitive data. Privacy compliance is excellent, with clear privacy and cookie policies, GDPR adherence, and minimal user tracking. The website lacks explicit public security policies or incident response pages, which could enhance transparency. Overall, Proton demonstrates a high level of trustworthiness, professionalism, and commitment to privacy and security. The risk assessment is low; no critical vulnerabilities or suspicious patterns were detected. Strategic recommendations include enabling DNSSEC, publishing detailed security and incident response policies, and maintaining transparency through vulnerability disclosures. Proton’s ecosystem includes related domains for account management and partner services, reinforcing its market position as a comprehensive privacy service provider.

Scanned

This is an earlier scan of protonmail.com. View the latest report

NIS2 and GDPR posture

GDPR outside view
53/ 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

4 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"

  2. GDPR outside view

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

    • 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

  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 protonmail.com

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

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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
65
Email security
80
DNS health
90
Network security
100
GDPR outside view
53
Average
77

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

Proton AG holds a strong market position as a leading provider of encrypted email and privacy services, targeting individuals, journalists, activists, and businesses concerned with data privacy. Its freemium business model balances free access with paid upgrades, fostering a large user base and steady revenue streams. The company’s Swiss base and compliance with strict privacy laws provide a competitive advantage. Partnerships with services like Proton VPN, Simple Login, and Standard Notes expand its ecosystem, enhancing user retention and cross-service integration. Growth indicators include over 100 million users and more than 50,000 business customers. Proton’s transparent open-source approach and independent audits strengthen its credibility and trust in the privacy community.

Security posture

Proton’s security maturity is high, leveraging end-to-end and zero-access encryption to ensure user data confidentiality. The company employs open-source encryption libraries audited independently, enhancing trust and security assurance. Domain registration status codes prevent unauthorized domain changes, and HTTPS is enforced site-wide. However, the absence of DNSSEC is a minor gap in DNS security. No public security policy or incident response contact was found, which could be improved to demonstrate readiness and transparency. No vulnerabilities or exposed sensitive data were detected. Proton’s security culture is evident in its product design and public communications, though formal documentation on incident response and vulnerability disclosure would strengthen posture further.

Recommendations

  1. Enable DNSSEC to enhance domain name system security and prevent DNS spoofing.
  2. Publish a comprehensive security policy and incident response plan accessible to users.
  3. Implement and publicize a vulnerability disclosure program and security.txt file.
  4. Increase transparency on certifications and compliance audits to boost user confidence.
  5. Maintain continuous security audits and update open-source libraries regularly.

Contact details published on the site

Addresses
Legal name
Proton AG
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
Proton AG
Description
Proton provides easy-to-use encrypted email, calendar, cloud storage, password manager, bitcoin wallet and VPN services, built on the principle of your data, your rules.
Key services
Encrypted email, Calendar, Cloud storage, Password manager, Bitcoin wallet, VPN services
Content quality
excellent
Branding
consistent

Technology

Stack
JavaScript, React, Astro framework, OpenPGP.js (implied from audit mention), CDN usage (pmecdn.protonweb.com)
Frameworks
Astro, React
Platforms
Web, iOS, Android, Windows, macOS, Linux
Performance
fast
Mobile
excellent
Accessibility
good
SEO
good

Security

Observed score
90/100
Good practices seen
  • End-to-end encryption
  • Zero-access encryption
  • Open source and audited encryption libraries
  • Client and server domain status protections

Analytics and tracking

Tracking level
minimal
Privacy practices
excellent

Advertising

Transparency
excellent

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.
  2. Strong emphasis on privacy, security, and Swiss jurisdiction.
  3. Comprehensive FAQ and product information available.
  4. No exposed sensitive data or security issues detected.
  5. Use of modern web technologies and good SEO practices.
  6. No direct contact emails or phone numbers found on main page; contact likely via account portal or support pages.
  7. No explicit security policy or incident response page found in main content.
  8. No visible cookie consent banner in provided content but cookie policy exists.
  9. Multiple external links to trusted Proton-related services and partners.
Technical notes

Notes

The website uses a modern tech stack including React and Astro, ensuring fast load times and excellent mobile responsiveness. The use of a CDN (pmecdn.protonweb.com) optimizes content delivery globally. The site is well-structured with proper meta tags, Open Graph, and JSON-LD structured data for SEO and social media integration. Accessibility features are present, and the design is professional and consistent. Hosting details are not explicitly stated but domain registration is via MarkMonitor Inc., a reputable registrar. No CMS was detected, suggesting a custom or static site generation approach. Overall, the technical implementation supports a high-quality user experience with minimal technical debt and good modernization practices.
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. 77/100Low26 findingsView report
  2. 77/100Low26 findingsView report
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