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Security report for crontab.guru

Cronitor.io · Technology · N/a

Medium risk. 9 critical or high findings in Email security, Security headers and 2 other checks.

Security score

60/100

Risk levelMedium

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

Crontab.guru is a specialized web tool designed to simplify the creation and understanding of cron schedule expressions. It serves primarily developers and system administrators who manage scheduled tasks. The website is closely integrated with Cronitor.io, a company offering cron job monitoring and alerting services, which is promoted throughout the site. Additionally, Crontab.guru offers a free, open source self-hosted dashboard for cron job management, enhancing its value proposition. The business model combines free tooling with promotion of paid monitoring services, positioning itself as a niche but valuable resource in the technology sector. Technically, the website is built using modern web standards including HTML5, CSS3, JavaScript, and SVG graphics. Hosting and DNS are managed via Amazon AWS infrastructure, indicating a reliable and scalable backend. The site is mobile optimized and performs well with good SEO practices. However, there is room for improvement in accessibility and security headers implementation. The site uses a JavaScript-based Real User Monitoring (RUM) script from Cronitor for analytics, reflecting a moderate level of user tracking. From a security perspective, the website enforces HTTPS and uses domain transfer protection status, which are positive indicators. However, it lacks DNSSEC and explicit security headers such as Content Security Policy or HSTS. No privacy or cookie policies are published, and no cookie consent mechanism is present, indicating compliance gaps with GDPR and related privacy regulations. No contact information or incident response channels are provided on the main page, limiting transparency. Overall, Crontab.guru is a trustworthy and professional site with a clear business focus and good technical foundation. To enhance its security posture and compliance, it should implement privacy and cookie policies, add security headers, enable DNSSEC, and provide clear contact and incident response information. These improvements would strengthen user trust and regulatory compliance while maintaining its strong market position in the cron tooling niche.

Scanned

This is an earlier scan of crontab.guru. View the latest report

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

9 findings rated critical or high. Fix these first.

  1. Email security

    SPF, DKIM and DMARC stop others sending email that looks like it comes from your domain, a common route to phishing and invoice fraud.

    • Critical

      No email authentication configured

      Domain is vulnerable to email spoofing

      What to do: Implement SPF, DKIM, and DMARC immediately

  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';…

  3. 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

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

Keep watching crontab.guru

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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
82
Security headers
15
Email security
40
DNS health
70
Network security
100
GDPR outside view
50
Average
60

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

Crontab.guru operates as a specialized tool within the technology sector, targeting developers and IT professionals managing cron jobs. Its competitive advantage lies in its simplicity, free access, and integration with Cronitor's monitoring services. The business model leverages free tooling to funnel users towards paid monitoring subscriptions, supported by an open source dashboard that encourages community engagement. The partnership ecosystem centers around Cronitor.io, which provides complementary services. Growth indicators include domain longevity since 2015 and consistent branding. The company maintains a lean operation with a small size profile, focusing on niche market penetration rather than broad diversification.

Security posture

The website demonstrates a moderate security maturity level with HTTPS enforced and domain transfer protection enabled. However, the absence of DNSSEC and security headers such as CSP and HSTS represents potential vulnerabilities. No exposed sensitive data or vulnerable libraries were detected. The lack of privacy and cookie policies, as well as missing incident response contact channels, indicates compliance gaps with GDPR and best practices. The use of a proprietary RUM script suggests controlled analytics without third-party trackers. Incident response readiness and security culture indicators are not evident from the public content, suggesting areas for improvement to enhance transparency and user trust.

Recommendations

  1. Enable DNSSEC on the domain to improve DNS security and prevent spoofing.
  2. Publish comprehensive privacy and cookie policies and implement a cookie consent mechanism to comply with GDPR.
  3. Add security headers such as Content Security Policy (CSP), HTTP Strict Transport Security (HSTS), X-Frame-Options, and X-Content-Type-Options.
  4. Provide clear contact information including security incident response channels (e.g., security@ or abuse@ email addresses).
  5. Consider publishing a security.txt file or vulnerability disclosure policy to encourage responsible reporting.
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
Cronitor.io
Description
An easy to use editor for crontab schedules. The site also offers a free, self-hosted open source dashboard for cron job control and promotes Cronitor's cron job monitoring services.
Key services
Cron schedule expression editor, Self-hosted cron job dashboard (open source), Cron job monitoring and alerting via Cronitor
Content quality
good
Branding
consistent

Technology

Stack
HTML5, CSS3, JavaScript, SVG, AWS Route 53 DNS
Performance
fast
Mobile
good
Accessibility
basic
SEO
good

Security

Observed score
85/100
Good practices seen
  • HTTPS enforced
  • No exposed sensitive data in HTML
  • No visible vulnerable libraries
  • Use of clientTransferProhibited domain status

Analytics and tracking

Services
Cronitor RUM
Tracking level
minimal
Privacy practices
poor

Advertising

Tracking pixels
Cronitor RUM
Transparency
basic

Site quality

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

Key observations

  1. Website is a specialized tool for cron schedule expression editing.
  2. Strong branding connection to Cronitor monitoring services.
  3. No privacy or cookie policies found, indicating compliance gaps.
  4. No contact emails or phone numbers explicitly provided on the main page.
  5. Use of modern web technologies and good mobile optimization.
  6. No security headers detected in HTML content; potential improvement area.
  7. No forms collecting personal data found on the main page.
  8. External links primarily to Cronitor services and GitHub for open source dashboard.
  9. No adult or questionable content detected.
  10. No WAF or blocking mechanisms detected.
Technical notes

Notes

The website is built on a modern, lightweight technology stack using standard HTML5, CSS3, and JavaScript, with SVG graphics for logos. Hosting is via Amazon AWS DNS infrastructure, indicating reliable and scalable backend services. The site is mobile optimized and loads quickly, with good SEO meta tags and Open Graph integration. No CMS or heavy frameworks were detected, suggesting minimal technical debt. The use of a custom JavaScript RUM script indicates in-house analytics capabilities. Opportunities exist to improve accessibility and implement additional security best practices such as security headers and DNSSEC. Overall, the technical implementation supports a fast, responsive, and professional 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. 60/100Medium33 findingsView report
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