Executive Summary

The GenerateBlocks plugin for WordPress has a vulnerability called Insecure Direct Object Reference (IDOR) in all versions up to and including 2.2.0. This happens because the plugin's REST endpoint /wp-json/generateblocks/v1/dynamic-tag-replacements only checks if a user has the edit_posts capability but does not verify if the user has permission to access the specific post or data referenced by the attacker-controlled id parameters.

As a result, authenticated users with Contributor-level access or higher can exploit this flaw to extract sensitive information from arbitrary posts. This includes author email addresses and non-protected post meta values by crafting special dynamic tag payloads.

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Impact Analysis

This vulnerability allows attackers with Contributor-level access or above to access sensitive information from posts they should not have permission to view. Specifically, they can extract author email addresses and non-protected post meta data from arbitrary posts.

Such unauthorized data disclosure can lead to privacy breaches, targeted phishing attacks, or other malicious activities leveraging the exposed information.

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Detection Guidance

Detection of this vulnerability involves identifying attempts to exploit the insecure REST endpoint /wp-json/generateblocks/v1/dynamic-tag-replacements by authenticated users with Contributor-level access or higher.

You can monitor your web server logs or use network monitoring tools to look for HTTP requests targeting the vulnerable endpoint with suspicious payloads containing dynamic tag patterns such as {{post_meta id:<target>|key:<meta_key>}} or {{post_title id:<target>|link:author_email}}.

Example commands to detect such activity might include:

• Using grep on web server access logs to find requests to the vulnerable endpoint: grep "/wp-json/generateblocks/v1/dynamic-tag-replacements" /var/log/apache2/access.log
• Searching for suspicious dynamic tag payloads in POST data or query parameters: grep -E "\{\{post_meta|\{\{post_title" /var/log/apache2/access.log
• Using tools like Wireshark or Zeek to monitor HTTP traffic for requests containing these patterns.

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Mitigation Strategies

Immediate mitigation steps include:

• Update the GenerateBlocks plugin to a version later than 2.2.0 where the vulnerability is fixed.
• Restrict access to the /wp-json/generateblocks/v1/dynamic-tag-replacements REST endpoint to trusted users only, or disable the endpoint if not needed.
• Review and limit user roles and capabilities, ensuring that only trusted users have Contributor-level access or higher.
• Monitor logs for suspicious activity targeting this endpoint and respond accordingly.

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Compliance Impact

The vulnerability allows authenticated attackers with Contributor-level access and above to extract sensitive information from arbitrary posts, including author email addresses and non-protected post meta values.

This unauthorized access to sensitive personal data could lead to non-compliance with data protection regulations such as GDPR and HIPAA, which require strict controls on access to personal and sensitive information.

Specifically, the exposure of author email addresses and other personal data without proper authorization checks may violate principles of data minimization and confidentiality mandated by these standards.

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