CVE-2023-4022 in Herd Effects Plugin
Summary
by MITRE • 09/11/2023
The Herd Effects WordPress plugin before 5.2.3 does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in multisite setup)
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Analysis
by VulDB Data Team • 10/10/2023
The vulnerability identified as CVE-2023-4022 affects the Herd Effects WordPress plugin version 5.2.2 and earlier, representing a critical stored cross-site scripting flaw that undermines the security of WordPress installations. This vulnerability specifically targets the plugin's handling of user settings, where insufficient sanitization and escaping mechanisms allow malicious code to be persistently stored within the application's database. The flaw is particularly concerning because it affects high-privilege users including administrators, who possess the capability to manipulate plugin configurations through the WordPress admin interface. The vulnerability becomes exploitable even in environments where the unfiltered_html capability has been restricted, such as in multisite WordPress setups where security controls are typically more stringent.
The technical implementation of this vulnerability stems from the plugin's failure to properly validate and sanitize user inputs within its settings management functionality. When administrators configure the plugin settings through the WordPress admin dashboard, the input values are not adequately processed to remove or escape potentially malicious script content. This improper handling creates a persistent XSS vector where malicious JavaScript code can be injected into the plugin's configuration parameters and subsequently executed whenever the settings are rendered or processed. The vulnerability is classified as a stored XSS attack because the malicious payload is saved in the database and executed each time the affected page is loaded, making it particularly dangerous for long-term persistence and impact.
The operational impact of this vulnerability extends beyond simple script execution, as it allows attackers with administrative privileges to potentially escalate their access within the WordPress environment. In multisite configurations where the unfiltered_html capability is typically restricted to prevent XSS attacks, this vulnerability effectively bypasses those security controls, undermining the layered defense mechanisms that site administrators have implemented. The vulnerability can be exploited to perform actions such as cookie theft, session hijacking, or redirection to malicious websites, potentially leading to full compromise of the WordPress installation. Additionally, the persistence of the stored payload means that the attack can affect multiple users over time, making it a significant threat to the overall security posture of the affected systems.
Mitigation strategies for CVE-2023-4022 focus primarily on immediate remediation through plugin updates to version 5.2.3 or later, which contains the necessary sanitization and escaping mechanisms. System administrators should also implement additional security measures including regular security audits of installed plugins, monitoring for unauthorized configuration changes, and maintaining up-to-date security policies that address input validation. The vulnerability aligns with CWE-79, which describes Cross-Site Scripting vulnerabilities, and can be mapped to ATT&CK technique T1548.001 for privilege escalation through modification of application code. Organizations should also consider implementing web application firewalls and input validation controls as additional defensive measures to protect against similar vulnerabilities in other plugins or applications.