Executive Summary

The Independent Analytics plugin for WordPress has a Server-Side Request Forgery (SSRF) vulnerability in all versions up to and including 2.14.9. This occurs because the plugin has a public tracking route (/wp-json/iawp/search) that accepts attacker-controlled referrer_url values when a signature matches. However, the signature validation is weak since the signature is embedded in publicly accessible JavaScript and the salt used is static per site, allowing attackers to extract valid signatures.

Additionally, the plugin includes a scheduled favicon fetcher that performs unrestricted cURL requests to stored domains without any SSRF protections such as localhost blocking or private network filtering. This means unauthenticated attackers can inject malicious referrer domains into the database and cause the server to make requests to arbitrary hosts, including internal services.

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Impact Analysis

This vulnerability can allow unauthenticated attackers to make the server perform requests to arbitrary hosts, including internal network services that are normally inaccessible from outside. This can lead to information disclosure, unauthorized access to internal resources, or further exploitation of internal services.

Because the attacker can inject malicious referrer domains and trigger server-side requests, it may also be possible to use this as a pivot point for additional attacks within the internal network.

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Mitigation Strategies

Immediate mitigation steps include updating the Independent Analytics plugin to a version later than 2.14.9 where this vulnerability is fixed.

If an update is not immediately possible, consider disabling or restricting access to the /wp-json/iawp/search endpoint to prevent unauthenticated attackers from exploiting the SSRF.

Additionally, monitor and restrict outgoing HTTP requests from the server to prevent abuse of the favicon fetcher functionality.

Implement network-level controls such as firewall rules to block unauthorized outbound requests to internal or sensitive network ranges.

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Detection Guidance

Detection of this vulnerability involves monitoring for unusual or unauthorized server-side requests initiated by the Independent Analytics plugin, especially requests to internal or unexpected external domains triggered via the /wp-json/iawp/search endpoint.

Since the vulnerability involves attacker-controlled referrer_url values and cURL requests without SSRF protections, you can look for suspicious entries in your web server logs or database where referrer_url values are stored.

Commands to help detect exploitation attempts might include:

• Using web server logs to search for requests to /wp-json/iawp/search with unusual or unexpected referrer_url parameters, e.g., `grep "/wp-json/iawp/search" /var/log/apache2/access.log`
• Checking database entries for suspicious referrer_url values that point to internal or unexpected hosts.
• Monitoring outgoing network connections from the server for unusual cURL requests to internal IP ranges or unexpected external domains.

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