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Security report for letsencrypt.org

Internet Security Research Group (ISRG) · 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, automated TLS certificates to over 700 million websites globally. Their mission is to make encryption accessible to everyone, improving Internet security and privacy. The organization is well-established since 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 multilingual support, detailed documentation, and active community engagement through forums and blogs. Technically, the site is built using the Hugo static site generator, employs modern JavaScript libraries like Plotly.js for data visualization, and is hosted with Cloudflare services, ensuring fast and secure delivery. Security posture is strong with HTTPS enforced and domain registration protections in place, though DNSSEC is not enabled, representing a minor area for improvement. Privacy compliance is robust with a clear privacy policy and terms of service linked, though no explicit cookie consent mechanism was detected. Overall, the website demonstrates high professionalism, trustworthiness, and technical maturity, supporting the nonprofit's mission effectively.

Scanned

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 SSL/TLS certificate market, disrupting traditional paid certificate authorities by offering automated and open certificate issuance. Their nonprofit business model is funded through sponsorships and donations, enabling wide adoption across diverse sectors including web hosting, software development, and online services. The organization targets website operators of all sizes, from individuals to enterprises, emphasizing ease of use and security. Their extensive partner ecosystem includes major technology companies and hosting providers, enhancing credibility and reach. Growth indicators such as over 700 million active certificates and detailed annual reports reflect sustained expansion and impact. Strategic partnerships and community engagement via forums and documentation further strengthen their market position and operational transparency.

Security posture

The website exhibits a mature security posture with mandatory HTTPS, domain registration safeguards (clientDeleteProhibited, clientTransferProhibited, clientUpdateProhibited), and hosting through Cloudflare, a reputable provider. No exposed sensitive data or vulnerable libraries were detected in the HTML content. However, DNSSEC is not enabled, which could enhance DNS security. The absence of a published security.txt or explicit incident response information is a minor gap in transparency for vulnerability reporting. Privacy compliance is strong with a comprehensive privacy policy and GDPR considerations evident. No signs of phishing, malware, or other security threats were found. Overall, the security posture supports the organization's trustworthiness and operational integrity.

Recommendations

  1. Enable DNSSEC on the domain to strengthen DNS security and prevent spoofing.
  2. Publish a security.txt file to facilitate responsible vulnerability disclosure and improve transparency.
  3. Add explicit security policy and incident response information on the website to enhance trust and preparedness.
  4. Implement a cookie consent mechanism to comply with evolving privacy regulations and improve user transparency.
  5. Regularly review and update third-party libraries and scripts to mitigate potential vulnerabilities.

Contact details published on the site

Addresses
Legal name
Internet Security Research Group (ISRG)
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
Internet Security Research Group (ISRG)
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 forum, Educational documentation and resources
Content quality
excellent
Branding
consistent

Technology

Stack
Hugo static site generator, FontAwesome icons, Plotly.js for charts, 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 DNS and registrar services

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 nonprofit branding and clear mission statement.
  3. Comprehensive multilingual support with many language options.
  4. Active community engagement via forums and blog.
  5. Strong sponsorship and partnership ecosystem.
  6. No signs of malicious or suspicious content.
  7. No visible forms collecting sensitive personal data on homepage.
  8. No explicit cookie consent banner detected.
  9. No security.txt or explicit vulnerability disclosure page found.
Technical notes

Notes

The website is built using the Hugo static site generator, ensuring fast and efficient content delivery. It leverages modern JavaScript libraries such as Plotly.js for interactive data visualization and FontAwesome for iconography. Hosting and DNS services are provided by Cloudflare, offering robust performance and security features. The site is mobile-optimized with responsive design and accessibility considerations, providing a good user experience across devices. SEO best practices are followed with proper meta tags and Open Graph data for social sharing. No CMS vulnerabilities or technical debt indicators were observed. Opportunities exist to enhance DNS security with DNSSEC and to formalize security disclosures. Overall, the technical infrastructure is modern, performant, and well-maintained.
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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