HIGH SEVERITYCMSCVSS 8.6Immediate (<90s)ID: zendesk
Zendesk Help Center Dangling DNS & Takeover Fingerprint
An organization's help center CNAME points to a Zendesk instance that has been closed or renamed. Attackers can register a new trial Zendesk instance with the same subdomain mapping.
DNS CNAME Delegation Rules
*.zendesk.com
CNAME points to *.zendesk.com. Webpage returns 'Help Center Closed'.
404 Not Found
Authoritative Response Token
“Help Center Closed”
curl -sI http://subdomain.example.com | grep 'Help Center Closed'When SubdomainWatch scanner identifies this response on an unresolved CNAME target, an automated alert is triggered within 800ms.
Remediation Guide & Defensive Action Plan
Immediate Action Required: Delete the host mapping CNAME in DNS or verify host mapping settings in your active Zendesk Admin Center.
Defensive Verification Checklist:
- Audit authoritative DNS zone records for any CNAME pointing to
*.zendesk.com. - Verify whether the target resource or bucket still exists under your organization's cloud tenant.
- If decommissioned, delete the DNS record immediately to close the public exposure window.
- Deploy a pre-merge IaC security gate (such as SubdomainWatch Takeover Guard) to intercept dangling records before pull requests merge.
Terraform Remediation Example
# Remove dangling Zendesk host mapping CNAME
ATTACK SURFACE DETECTION COMPARISON
Why Static DNS Scanners Miss Zendesk Help Center Takeovers
Passive DNS repositories like SecurityTrails and heavy scanners like Detectify record domain records retrospectively or trigger alert fatigue. SubdomainWatch conducts active recursive CNAME testing with zero false positives.
Zendesk Help Center Takeover FAQs
Support subdomains (e.g. support.example.com) carry high user trust. Hijackers can harvest user credentials, session cookies, or intercept customer support tickets.
FREE UNRESTRICTED SCANNER
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