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Security report for letsencrypt.org

Internet Security Research Group · Technology · United States

Low risk. 3 critical or high findings in GDPR outside view and SSL/TLS.

Security score

83/100

Risk levelLow

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

Let's Encrypt is a leading nonprofit Certificate Authority operated by the Internet Security Research Group (ISRG), providing free and automated TLS certificates to over 650 million websites globally. Their mission is to make HTTPS encryption accessible to everyone, enhancing Internet security and privacy. The organization is well-established, founded in 2014, and supported by major technology sponsors such as Google, AWS, Mozilla, and the Electronic Frontier Foundation. The website reflects a mature digital presence with comprehensive documentation, community support, and transparent nonprofit operations. Technically, the website is built using modern technologies including the Hugo static site generator, Cloudflare DNS and registrar services, and Plotly.js for data visualization. It demonstrates excellent performance, mobile optimization, and accessibility. The site enforces HTTPS and employs domain status protections to prevent unauthorized domain changes. However, DNSSEC is not enabled, representing a minor security enhancement opportunity. From a security perspective, Let's Encrypt maintains a strong posture with no detected vulnerabilities or exposed sensitive data. The absence of a published security policy or incident response contact is noted, as is the lack of a security.txt file for vulnerability disclosure. Privacy compliance is robust, with a clear privacy policy and GDPR adherence, though no cookie consent mechanism was detected. The business credibility is high, supported by transparent WHOIS data and consistent domain registration details. Overall, Let's Encrypt's website is professional, trustworthy, and aligned with its nonprofit mission. Strategic recommendations include enabling DNSSEC, publishing a security.txt file, and enhancing transparency around security policies and incident response to further strengthen trust and compliance.

Scanned

This is an earlier scan of letsencrypt.org. View the latest report

NIS2 and GDPR posture

GDPR outside view
58/ 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

3 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.

    • 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.

    • High

      Weak SSL Key Length

      SSL certificate uses 256-bit key, which is considered weak

      What to do: Use at least 2048-bit RSA or 256-bit ECC key

      • CWE-326
      • OWASP A04:2025
      • Mozilla TLS: Mozilla Server Side TLS 6.0 intermediate: rsa_key_size 2048

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  • 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
95
Email security
85
DNS health
85
Network security
100
GDPR outside view
58
Average
83

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

Let's Encrypt occupies a dominant position in the free TLS certificate market, disrupting traditional paid certificate authorities by offering automated and accessible encryption solutions. Their nonprofit model is funded through sponsorships and donations from major technology companies and foundations, ensuring sustainability without commercial pressure. The target audience includes website owners, developers, and organizations seeking to secure their web presence. The extensive partner ecosystem and community engagement foster widespread adoption and trust. Growth indicators such as over 650 million certificates issued and detailed annual reports demonstrate strong market traction and operational transparency.

Security posture

The security maturity of Let's Encrypt is high, with enforced HTTPS, domain registration protections, and no visible vulnerabilities or sensitive data leaks. The lack of DNSSEC is a minor gap that could be addressed to improve DNS security. The absence of explicit security policy documentation and incident response contacts suggests room for improvement in transparency and readiness. Privacy practices are strong, with GDPR compliance and a comprehensive privacy policy. No tracking or advertising scripts were detected, minimizing privacy risks. Overall, the security posture supports the organization's mission and user trust but could benefit from formalized vulnerability disclosure and incident response mechanisms.

Recommendations

  1. Enable DNSSEC on the domain to enhance DNS security and integrity.
  2. Publish a security.txt file to provide clear vulnerability disclosure and contact information.
  3. Develop and publish a formal security policy outlining frameworks and controls.
  4. Implement a cookie consent mechanism if cookies are used to comply with privacy regulations.
  5. Add explicit incident response contact channels to improve transparency and readiness.

Contact details published on the site

Addresses
Legal name
Internet Security Research Group
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
Internet Security Research Group
Description
Let's Encrypt is a nonprofit Certificate Authority providing free, automated TLS certificates to enable HTTPS encryption for websites worldwide.
Key services
Free TLS/SSL certificate issuance, Automated certificate management via ACME protocol, Community support and documentation
Content quality
excellent
Branding
consistent

Technology

Stack
Hugo static site generator, Cloudflare DNS and registrar, FontAwesome icons, Plotly.js for data visualization, JavaScript for UI interactions
Performance
fast
Mobile
excellent
Accessibility
good
SEO
good

Security

Observed score
90/100
Good practices seen
  • HTTPS enforced
  • Domain status includes clientDeleteProhibited, clientTransferProhibited, clientUpdateProhibited
  • No exposed sensitive data in HTML
  • Use of Cloudflare for DNS and registrar

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 no blocking or WAF challenges.
  2. Content is rich, professionally presented, and well-structured.
  3. Strong nonprofit branding and clear mission statement.
  4. Comprehensive sponsorship and partner ecosystem.
  5. No signs of tracking or advertising networks.
  6. No exposed sensitive data or security vulnerabilities detected.
  7. DNSSEC is not enabled, which is a minor security improvement opportunity.
Technical notes

Notes

The website leverages a modern static site generator (Hugo) combined with Cloudflare's DNS and registrar services, ensuring fast and reliable hosting. The use of Plotly.js enables rich data visualization for transparency on certificate issuance and usage. The site is mobile-optimized, accessible, and SEO-friendly with proper meta tags and Open Graph data. No legacy or vulnerable libraries were detected. The absence of DNSSEC is a technical gap. Overall, the infrastructure is robust, performant, and well-maintained, supporting the organization's operational needs and 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. 83/100Low21 findingsView report
  2. 83/100Low21 findingsView report
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