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Security report for zulip.org

Kandra Labs, Inc. · Technology · N/a

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

Security score

79/100

Risk levelLow

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

Zulip, operated by Kandra Labs, Inc., is a mature and well-established technology company specializing in organized team chat solutions tailored for distributed teams of all sizes. The platform emphasizes asynchronous communication, offering both cloud-hosted services and a fully open-source self-hosted option, catering to businesses, educational institutions, research groups, open source projects, and communities. The website reflects a professional and consistent brand image with comprehensive content, customer testimonials, and case studies that reinforce its market position as a niche but competitive player in the team collaboration space. Technically, the website employs modern JavaScript technologies with Webpack bundling, integrates Google Analytics and Tag Manager for user tracking, and uses Sentry for error monitoring. Hosting is inferred to be on Amazon AWS, supported by AWS nameservers. The site is fast, mobile-optimized, and accessible, with good SEO practices. However, DNSSEC is not enabled, and explicit security headers are not visible in the provided data, suggesting room for improvement in DNS and HTTP security hardening. From a security perspective, the site enforces HTTPS and uses domain transfer protection. The availability of a dedicated security page and open-source software for self-hosting enhances trust. No critical vulnerabilities or exposed sensitive data were detected. However, the absence of a public vulnerability disclosure policy or security.txt file and lack of incident response contact details are gaps. Privacy compliance is strong with a comprehensive privacy policy and terms of service, though no cookie consent mechanism was detected despite analytics usage. Overall, Zulip presents a low-risk profile with a strong business and technical foundation. Strategic improvements in DNS security, security headers, and transparency around vulnerability disclosure and incident response would further enhance its security posture and trustworthiness.

Scanned

NIS2 and GDPR posture

GDPR outside view
65/ 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 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 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 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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Keep watching zulip.org

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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
80
Security headers
50
Email security
95
DNS health
85
Network security
100
GDPR outside view
65
Average
79

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

Zulip operates in the technology sector, focusing on team collaboration software with a unique asynchronous communication model. Its business model combines SaaS offerings with open-source self-hosted software, appealing to a broad range of customers from small businesses to large enterprises, educational institutions, and open source communities. The company leverages a strong partnership ecosystem, including integrations and community engagement. The presence of detailed case studies and testimonials indicates a mature customer base and effective market penetration. The company’s longevity since 2010 and consistent domain registration data support its credibility. Revenue streams likely include subscription plans for hosted services and enterprise support. The company maintains active social media channels and a development community, reinforcing its market presence and growth potential.

Security posture

Zulip demonstrates a solid security posture with HTTPS enforced and domain transfer protection enabled. The open-source nature of the software allows customers to self-host and control their data, which is a significant security and privacy advantage. The website links to a dedicated security page, indicating organizational awareness of security best practices. However, the lack of DNSSEC and absence of explicit security headers such as Content Security Policy or HSTS are areas for improvement. No public vulnerability disclosure or incident response contacts were found, which could hinder coordinated vulnerability management. Analytics and tracking scripts are present but privacy policies are comprehensive, suggesting balanced data protection practices. Overall, the security maturity is good but could be enhanced by adopting additional DNS and HTTP security measures and publishing vulnerability handling policies.

Recommendations

  1. Enable DNSSEC on the domain to improve DNS integrity and prevent spoofing.
  2. Implement and publish a security.txt file and a clear vulnerability disclosure policy.
  3. Add and enforce HTTP security headers such as Content Security Policy, HSTS, and X-Frame-Options.
  4. Provide explicit incident response contact information on the website.
  5. Introduce a cookie consent mechanism to comply fully with privacy regulations given the use of tracking scripts.
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
Kandra Labs, Inc.
Description
Zulip is an organized team chat app for distributed teams of all sizes.
Key services
Team chat application, Cloud-hosted chat service, Self-hosted open-source chat server, Integrations and APIs, Desktop and mobile apps
Content quality
excellent
Branding
consistent

Technology

Stack
JavaScript, Webpack, Google Analytics, Google Tag Manager, Sentry
Platforms
Web, Desktop apps, Mobile apps
Performance
fast
Mobile
excellent
Accessibility
good
SEO
good

Security

Observed score
85/100
Good practices seen
  • HTTPS enforced
  • ClientTransferProhibited domain status
  • Open source software allowing self-hosting for control
  • Security page linked

Analytics and tracking

Services
Google Analytics, Google Tag Manager, Sentry
Tracking level
moderate
Privacy practices
good

Advertising

Transparency
basic

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 navigation.
  2. Strong emphasis on asynchronous team chat for distributed teams.
  3. Open source and self-hosting options enhance trust and control.
  4. No direct contact emails or phone numbers found on main pages.
  5. Social media presence on Twitter, Mastodon, LinkedIn.
  6. No cookie consent banner detected despite analytics usage.
  7. No explicit vulnerability disclosure or security.txt found.
  8. Domain DNSSEC not enabled, which is a minor security gap.
Technical notes

Notes

The website uses a modern JavaScript stack with Webpack for bundling and integrates third-party services like Google Analytics, Google Tag Manager, and Sentry for analytics and error tracking. Hosting is likely on AWS, supported by AWS DNS nameservers. The site is well-optimized for performance and mobile devices, with responsive design and good accessibility features. SEO is well addressed with proper meta tags and Open Graph data. The absence of a known CMS suggests a custom or bespoke platform. Technical debt appears low, but improvements in DNS security and HTTP headers could reduce risk. Overall, the technical infrastructure is robust, scalable, and aligned with industry best 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

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