CVE-2024-3972 in Similarity Plugin
Summary
by MITRE • 06/14/2024
The Similarity WordPress plugin through 3.0 does not have CSRF check in some places, and is missing sanitisation as well as escaping, which could allow attackers to make logged in admin add Stored XSS payloads via a CSRF attack
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Analysis
by VulDB Data Team • 03/23/2025
The vulnerability identified as CVE-2024-3972 affects the Similarity WordPress plugin version 3.0 and earlier, presenting a critical security risk that combines multiple dangerous flaws. This issue stems from the plugin's failure to implement proper cross-site request forgery protection mechanisms in certain administrative functions while simultaneously lacking adequate input sanitization and output escaping measures. The combination of these weaknesses creates a pathway for attackers to execute stored cross-site scripting attacks against authenticated administrators.
The technical flaw manifests in the plugin's administrative interface where CSRF protection mechanisms are absent or insufficient, allowing attackers to craft malicious requests that can be executed when administrators perform legitimate administrative tasks. The vulnerability is particularly concerning because it leverages the trust relationship between the administrator's browser and the WordPress installation. When an authenticated admin user visits a malicious website or clicks on a compromised link, the attacker can inject malicious JavaScript payloads that get stored within the WordPress database. These payloads then execute whenever the admin user views affected pages, creating a persistent XSS attack vector.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with a foothold for more sophisticated attacks. Once an attacker successfully injects malicious code through the stored XSS vector, they can steal admin session cookies, modify content, redirect users to malicious sites, or even escalate privileges within the WordPress environment. The vulnerability's persistence stems from the stored nature of the XSS payload, meaning that the malicious code remains active even after the initial attack window has passed. This characteristic makes the vulnerability particularly dangerous for high-privilege accounts and can lead to complete compromise of the WordPress installation.
Security professionals should note that this vulnerability aligns with CWE-352, which specifically addresses cross-site request forgery issues, and CWE-79, which covers cross-site scripting vulnerabilities. The attack pattern follows typical ATT&CK techniques categorized under T1566 for credential access through social engineering and T1059 for command and scripting interpreter usage. Organizations should immediately update to the latest version of the Similarity plugin where these security flaws have been addressed, implement proper input validation and output escaping mechanisms, and consider additional security measures such as content security policies and web application firewalls to provide defense-in-depth protection against similar vulnerabilities.
Mitigation strategies should include immediate patching of the affected plugin version, implementing proper CSRF token validation across all administrative endpoints, and ensuring that all user inputs are properly sanitized before being stored in the database. Additionally, administrators should monitor their WordPress installations for any signs of compromise and consider implementing automated security scanning tools to detect similar vulnerabilities in other plugins or themes. The vulnerability serves as a reminder of the critical importance of proper security practices in WordPress plugin development, particularly around authentication verification and input/output handling.