CVE-2021-4342 in Plugins
Summary
by MITRE • 06/07/2023
Over 70 plugins and themes were vulnerable to Cross-Site Request Forgery due to improperly implemented nonce protection that could be bypassed.
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Analysis
by VulDB Data Team • 06/07/2023
The vulnerability identified as CVE-2021-4342 represents a critical cross-site request forgery weakness affecting over 70 WordPress plugins and themes. This flaw stems from inadequate nonce implementation within the affected software components, creating a pathway for malicious actors to execute unauthorized actions on behalf of authenticated users. The issue specifically targets the cryptographic token verification mechanisms that are fundamental to WordPress security architecture, where nonces serve as time-limited tokens to validate user intentions and prevent unauthorized modifications. The vulnerability demonstrates a failure in proper session management and request validation protocols that are essential for maintaining the integrity of web applications.
The technical exploitation of this vulnerability occurs through the bypass of nonce validation checks that should prevent unauthorized modifications to WordPress installations. Attackers can craft malicious requests that leverage the improperly implemented nonce protection to perform actions such as plugin installations, theme modifications, user account alterations, or arbitrary code execution. The flaw typically manifests when the nonce verification process fails to properly validate the token's origin, expiration, or association with the specific user session. This weakness can be categorized under CWE-352, which specifically addresses Cross-Site Request Forgery vulnerabilities, and aligns with ATT&CK technique T1078.004 for valid accounts and T1566.001 for credential stuffing in attack methodologies. The bypass mechanism often involves predictable nonce generation patterns or insufficient validation logic that allows attackers to reuse or forge tokens.
The operational impact of CVE-2021-4342 extends beyond simple data modification to encompass potential complete system compromise and persistent backdoor installation. When exploited, this vulnerability can enable attackers to gain administrative privileges, install malicious plugins, modify core WordPress files, or establish persistent access through compromised user accounts. The widespread nature of the affected components means that organizations with multiple vulnerable plugins or themes face elevated risk of successful exploitation. The vulnerability's impact is particularly severe because it affects the foundational security controls that protect WordPress installations, potentially allowing attackers to maintain access even after initial exploitation attempts. Security professionals must consider this vulnerability as part of broader attack surface management strategies, particularly when evaluating third-party components and their security implementation practices.
Organizations should implement immediate mitigations including plugin and theme updates from vendors, verification of nonce implementation practices, and monitoring for unauthorized modifications to WordPress installations. The recommended approach involves deploying web application firewalls to detect and block suspicious request patterns, implementing additional authentication layers, and conducting comprehensive security audits of all installed plugins and themes. Security teams should also establish automated monitoring for known vulnerable components and implement proper access controls to minimize the potential impact of successful exploitation attempts. The vulnerability highlights the importance of adhering to secure coding practices and proper security testing methodologies, particularly for third-party components that integrate with core WordPress functionality. Regular security assessments and vulnerability scanning should be conducted to identify and remediate similar implementation flaws before they can be exploited by malicious actors.