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Security report for slack.com

Slack · Technology · United States

Low risk. 3 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

Slack is a leading enterprise collaboration platform owned by Salesforce, providing a comprehensive suite of tools for team communication, project management, workflow automation, and AI-powered productivity enhancements. The website reflects Slack's strong market position with extensive content targeting businesses and enterprises seeking modern work management solutions. Technically, the site leverages modern JavaScript frameworks, AWS hosting, and CDN services to deliver fast, responsive, and accessible user experiences. Security posture is robust, with HTTPS enforced, multiple security headers, and public documentation of compliance certifications such as SOC 2 and ISO 27001. Privacy compliance is well addressed with clear policies and consent mechanisms. Overall, Slack's digital presence is professional, trustworthy, and aligned with enterprise standards.

Scanned

NIS2 and GDPR posture

GDPR outside view
68/ 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. 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 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 slack.com

This scan found 17 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.

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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
62
Security headers
55
Email security
85
DNS health
90
Network security
100
GDPR outside view
68
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

Slack operates on a SaaS subscription model targeting large enterprises and businesses across various industries, primarily in technology. Its integration with Salesforce and partnerships with companies like OpenAI enhance its competitive advantage. The platform's extensive app marketplace and AI agent capabilities position it as a versatile tool for digital workplace transformation. Customer testimonials and case studies from major brands reinforce its market credibility and adoption. Slack's business model emphasizes collaboration, productivity, and AI integration, catering to a broad audience from IT and engineering to marketing and sales departments.

Security posture

Slack demonstrates a mature security posture with enforced HTTPS, comprehensive security headers, and domain registration protections. The presence of enterprise key management and detailed security documentation indicates strong data protection practices. However, the absence of a published security.txt and explicit incident response contact details suggests room for improvement in vulnerability disclosure and incident communication. No exposed sensitive data or known vulnerabilities were detected in the website content. Compliance with GDPR and other regulations is indicated through privacy policies and cookie consent mechanisms.

Recommendations

  1. Enable DNSSEC to enhance DNS security and prevent spoofing.
  2. Publish a security.txt file to facilitate responsible vulnerability disclosure.
  3. Provide explicit incident response contact information to improve transparency.
  4. Regularly audit third-party scripts and tracking tools to minimize privacy risks.
  5. Enhance accessibility features to achieve excellent compliance with standards.
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
Slack
Description
Slack is where work happens. Bring your people, projects, tools, and AI together on the world’s most beloved work operating system.
Key services
Team collaboration, Messaging, Project management, Workflow automation, AI-powered agents, Enterprise key management
Content quality
excellent
Branding
consistent

Technology

Stack
JavaScript, AWS (implied by AWS DNS servers), Cloudfront CDN, YouTube iframe API
Platforms
Web, Mobile (responsive design)
Performance
fast
Mobile
excellent
Accessibility
good
SEO
good

Security

Observed score
90/100
Good practices seen
  • HTTPS enforced
  • Domain status protections (clientDeleteProhibited, clientTransferProhibited, etc.)
  • Enterprise Key Management
  • Security and compliance documentation publicly available

Analytics and tracking

Services
Optimizely, Google Tag Manager, Clearbit
Tracking level
moderate
Privacy practices
good

Advertising

Tracking pixels
Optimizely, OneTrust
Marketing tools
Clearbit
Transparency
good

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 multimedia.
  2. Strong branding and consistent messaging throughout.
  3. Comprehensive navigation with clear categorization of features, solutions, resources, and enterprise offerings.
  4. Use of modern web technologies and CDNs for performance.
  5. Privacy and cookie policies are present with consent mechanisms.
  6. Security and compliance information is prominently available.
  7. No exposed sensitive data or security vulnerabilities detected in the content.
  8. No direct contact emails or phone numbers publicly listed; contact via forms and sales pages.
  9. Integration with major partners like Salesforce and OpenAI is highlighted.
  10. Use of tracking and analytics tools is disclosed and consent managed.
Technical notes

Notes

The website is built on a modern technology stack including JavaScript and likely React, hosted on AWS with Cloudfront CDN for performance optimization. It employs multiple external services such as YouTube for video content and OneTrust for cookie consent management. The site is mobile-optimized with responsive design and accessibility considerations. SEO is well implemented with comprehensive meta tags and Open Graph data. No technical debt or outdated libraries were detected in the provided content. The infrastructure supports fast loading times and a seamless 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. 77/100 −3Low26 findingsView report
  2. 80/100 +7Low24 findingsView report
  3. 73/100Medium22 findingsView report
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