CVE-2021-34629 in SendGrid Plugin
Summary
by MITRE • 07/31/2021
The SendGrid WordPress plugin is vulnerable to authorization bypass via the get_ajax_statistics function found in the ~/lib/class-sendgrid-statistics.php file which allows authenticated users to export statistic for a WordPress multi-site main site, in versions up to and including 1.11.8.
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Analysis
by VulDB Data Team • 08/06/2021
The vulnerability identified as CVE-2021-34629 affects the SendGrid WordPress plugin, specifically targeting versions up to and including 1.11.8. This authorization bypass flaw exists within the get_ajax_statistics function located in the ~/lib/class-sendgrid-statistics.php file, creating a significant security risk for WordPress multi-site installations. The vulnerability allows authenticated users to access and export statistical data from the main site of a WordPress multi-site network, potentially exposing sensitive information about email delivery metrics and user engagement patterns.
The technical implementation of this vulnerability stems from insufficient access controls within the plugin's statistics export functionality. When authenticated users invoke the get_ajax_statistics function, the plugin fails to properly validate whether the requesting user has appropriate permissions to access statistics from the main site in a multi-site environment. This misconfiguration creates an unintended privilege escalation path where users with basic authentication credentials can bypass normal access restrictions and retrieve data that should be restricted to administrators or site owners. The flaw is particularly concerning in multi-site configurations where different users may have varying levels of access rights but can exploit this function to access data from the primary site.
The operational impact of this vulnerability extends beyond simple data exposure, as it can enable attackers to gather intelligence about email campaign performance, user engagement patterns, and delivery statistics that could inform future targeted attacks. In a multi-site WordPress environment, this vulnerability could allow malicious actors to gather information about email infrastructure, identify successful campaigns, and potentially correlate this data with other reconnaissance efforts. The exported statistics might reveal sensitive details about user behavior, campaign effectiveness, and system performance that could be leveraged for social engineering attacks or to plan more sophisticated breaches. This vulnerability particularly affects organizations that rely heavily on email marketing and communication, as the exported data could provide valuable insights into their marketing strategies and user engagement metrics.
Organizations should immediately upgrade to the patched version of the SendGrid WordPress plugin to address this authorization bypass vulnerability. The mitigation strategy should include implementing additional access controls at the WordPress level, monitoring user activities for suspicious access patterns, and ensuring proper role-based access controls are in place for multi-site installations. Security teams should also consider implementing network-level monitoring to detect unusual data export activities and establish automated alerts for unauthorized access attempts to statistical data. This vulnerability aligns with CWE-284, which addresses improper access control issues, and represents a clear violation of the principle of least privilege. The ATT&CK framework categorizes this as a privilege escalation technique where an attacker gains elevated access rights through flawed authorization mechanisms, making it a critical vulnerability requiring immediate remediation.