CAPTCHA Bypass in pH7Builder CMS

Executive Summary

This vulnerability is a CAPTCHA bypass in pH7Builder versions before 19.3.0. It allows unauthenticated attackers to skip CAPTCHA validation by providing a client-chosen form ID to the PFBC Form::isValid() function. Attackers can load forms like login or search without CAPTCHA and submit data through forms such as contact, comment, forum, invite, or signup by exploiting this flaw.

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Detection Guidance

Check if your pH7Builder version is below 19.3.0 by inspecting the version file or running a version check command. Monitor form submissions for unusual patterns like automated contact, comment, or signup attempts without CAPTCHA completion.

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Impact Analysis

This vulnerability enables automated abuse of forms, such as spam submissions, brute-force login attempts, or automated account creation. Attackers can bypass security measures to flood systems with fake requests, leading to resource exhaustion, degraded performance, or compromised user accounts. It undermines the intended security of CAPTCHA-protected forms.

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Compliance Impact

This vulnerability could potentially impact compliance with GDPR and HIPAA by enabling automated abuse of forms that handle sensitive user data. For GDPR, automated form submissions could lead to unauthorized processing of personal data, violating principles of lawfulness and fairness. For HIPAA, if the software processes protected health information in forms like contact or signup, the bypass could allow unauthorized access or disclosure of PHI through automated submissions.

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Mitigation Strategies

Update pH7Builder to version 19.3.0 or later immediately. Review form validation logic to ensure hardcoded form IDs are used instead of dynamic POST values. Apply the security patch from the GitHub commit referenced in Resource 3.

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