CVE-2022-2556 in Mailchimp for WooCommerce Plugin
Summary
by MITRE • 08/29/2022
The Mailchimp for WooCommerce WordPress plugin before 2.7.2 has an AJAX action that allows high privilege users to perform a POST request on behalf of the server to the internal network/LAN, the body of the request is also appended to the response so it can be used to scan private network for example
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Analysis
by VulDB Data Team • 10/09/2022
The vulnerability identified as CVE-2022-2556 affects the Mailchimp for WooCommerce WordPress plugin version 2.7.1 and earlier, representing a critical server-side request forgery (SSRF) flaw that enables authenticated attackers with high privilege user roles to execute unauthorized network requests from the affected server. This issue stems from insufficient input validation and access control mechanisms within the plugin's AJAX handling functionality, creating a pathway for malicious actors to leverage the server's network connectivity for unauthorized reconnaissance and exploitation activities. The vulnerability specifically resides in the plugin's ability to process POST requests through an exposed AJAX endpoint without proper authorization checks, allowing privilege escalation attacks that bypass normal network security boundaries.
The technical implementation of this vulnerability involves the plugin's AJAX action handler which accepts external POST requests and subsequently forwards them to internal network resources without adequate sanitization or access control measures. When an authenticated user with sufficient privileges triggers this endpoint, the server executes the specified network request on behalf of the WordPress installation, effectively enabling an attacker to perform network scanning operations against internal systems that would normally be protected by network segmentation. The malicious behavior is amplified by the fact that the response body from these internal requests is directly appended to the plugin's response, providing attackers with immediate feedback about the scanned network resources and their accessibility.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates a persistent attack vector that can be exploited for comprehensive internal network reconnaissance. Attackers can leverage this flaw to enumerate internal services, identify vulnerable systems, and potentially discover additional attack surfaces within the organization's network infrastructure. The vulnerability enables a form of network scanning that operates entirely within the bounds of legitimate server functionality, making detection more challenging as the malicious activity appears to originate from legitimate internal network traffic. This capability significantly increases the risk of subsequent exploitation attempts targeting other internal systems that may be discovered through the initial scanning phase.
Security professionals should consider this vulnerability in the context of CWE-918, which addresses server-side request forgery issues, and aligns with ATT&CK techniques focused on reconnaissance and initial access phases. The flaw demonstrates a clear path for attackers to move laterally within network environments, potentially leading to more severe compromises. Organizations should implement immediate mitigations including plugin updates to version 2.7.2 or later, which address the access control deficiencies in the AJAX handling code. Additionally, network segmentation strategies should be reinforced to limit the potential impact of such vulnerabilities, while monitoring systems should be enhanced to detect anomalous network request patterns originating from WordPress installations. The vulnerability also underscores the importance of proper input validation and privilege separation in web application development practices, particularly when handling external request forwarding mechanisms that could inadvertently expose internal network resources to unauthorized access.