Netcccyun DNSMgr Missing Authorization in Domain Enumeration

Executive Summary

This vulnerability is a missing authorization issue in the dnsmgr software (versions 2.18 to 2.21) affecting the Cloudflare default-line endpoint. It allows restricted users, such as sub-users or single-domain guests, to bypass permission checks by manipulating the domain_id parameter. Attackers can enumerate domain IDs and read DNS line configurations of domains they are not authorized to access.

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Detection Guidance

To detect this vulnerability, monitor HTTP POST requests to /cloudflare/get_domain_default_line. Check if restricted users can access domains outside their permissions by enumerating domain_id parameters. Look for unauthorized access attempts or unusual DNS configuration retrievals.

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Impact Analysis

This vulnerability allows unauthorized users to access sensitive DNS configuration data of other domains, leading to information disclosure. While it does not allow direct record modification or credential theft, attackers can enumerate domains and retrieve provider-specific line configurations, potentially exposing confidential DNS settings.

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Compliance Impact

This vulnerability could lead to non-compliance with GDPR and HIPAA due to unauthorized access to sensitive DNS configuration data. GDPR requires protection of personal data, while HIPAA mandates safeguarding protected health information. Unauthorized access to such data may result in violations of these regulations.

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Mitigation Strategies

Apply the latest patch from commit 175468c6423c04a6b46e56663c37f090bef5381f. Ensure the get_domain_default_line() method includes checkPermission(0, $domainRow['name']) to enforce authorization checks. Restrict access to the endpoint and monitor for suspicious activity.

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