CVE-2021-24452 in W3 Total Cache Plugin
Summary
by MITRE • 07/19/2021
The W3 Total Cache WordPress plugin before 2.1.5 was affected by a reflected Cross-Site Scripting (XSS) issue within the "extension" parameter in the Extensions dashboard, when the 'Anonymously track usage to improve product quality' setting is enabled, as the parameter is output in a JavaScript context without proper escaping. This could allow an attacker, who can convince an authenticated admin into clicking a link, to run malicious JavaScript within the user's web browser, which could lead to full site compromise.
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Analysis
by VulDB Data Team • 01/27/2023
The vulnerability identified as CVE-2021-24452 affects the W3 Total Cache WordPress plugin, a widely used performance optimization tool that has been compromised by a reflected cross-site scripting flaw in versions prior to 2.1.5. This vulnerability specifically targets the Extensions dashboard functionality where the plugin processes user input through the "extension" parameter without adequate sanitization or escaping mechanisms. The flaw manifests when the plugin's anonymous usage tracking feature is enabled, creating a dangerous scenario where untrusted input flows directly into JavaScript contexts within the browser environment. The vulnerability falls under CWE-79 which specifically addresses cross-site scripting flaws, and represents a classic reflected XSS attack vector that exploits how web applications handle and output user-supplied data.
The technical exploitation of this vulnerability occurs when an authenticated administrator user visits a maliciously crafted URL containing the XSS payload within the extension parameter. When the plugin processes this parameter in the Extensions dashboard, it fails to properly escape the input before rendering it in a JavaScript context, allowing the attacker to inject malicious scripts that execute within the administrator's browser session. The security implications are severe because administrators possess elevated privileges within the WordPress environment, making successful exploitation potentially catastrophic for site security. The attacker could leverage this vulnerability to execute arbitrary JavaScript code, potentially stealing session cookies, modifying content, or even gaining full administrative control over the WordPress installation. This represents a critical privilege escalation vector that transforms a simple XSS flaw into a full site compromise capability.
The operational impact of CVE-2021-24452 extends beyond immediate code execution as it creates persistent security risks for WordPress installations using vulnerable versions of W3 Total Cache. The requirement for an authenticated admin user to click a malicious link means that social engineering becomes a critical attack vector, but once exploited, the consequences can be devastating. Attackers can leverage this vulnerability to establish persistent backdoors, exfiltrate sensitive data, modify website content, or even deploy malware across the entire WordPress ecosystem. The vulnerability's presence in the Extensions dashboard also means that attackers could potentially manipulate plugin functionality or gain insights into the site's configuration. According to ATT&CK framework, this vulnerability maps to T1059.007 for command and scripting interpreter and T1566 for credential access, as it enables attackers to execute malicious code and potentially harvest administrative credentials. Organizations running vulnerable versions face significant exposure risk, particularly those with less security-aware administrators who might be susceptible to phishing attacks or other social engineering techniques that could lead them to click malicious links.
Mitigation strategies for CVE-2021-24452 primarily involve immediate patching of the W3 Total Cache plugin to version 2.1.5 or later, which contains the necessary fixes to properly escape user input before rendering it in JavaScript contexts. Administrators should also implement additional security measures including regular security audits, monitoring for suspicious user activity, and implementing web application firewalls that can detect and block malicious payloads. The vulnerability demonstrates the critical importance of input validation and output escaping in web applications, particularly in contexts where user input directly influences JavaScript execution. Security teams should also consider implementing role-based access controls and multi-factor authentication to reduce the impact of successful exploitation attempts. Organizations should conduct thorough security assessments to identify all instances of vulnerable plugin versions and ensure that all WordPress installations maintain up-to-date security patches. The vulnerability serves as a reminder of the importance of maintaining current security practices and the potential consequences of neglecting plugin security updates in WordPress environments.