CVE-2021-4411 in WP EasyPay Plugin
Summary
by MITRE • 07/12/2023
The WP EasyPay – Square for WordPress plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 3.2.0. This is due to missing or incorrect nonce validation on the wpep_download_transaction_in_excel() function. This makes it possible for unauthenticated attackers to trigger a transactions download via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.
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Analysis
by VulDB Data Team • 07/12/2023
The WP EasyPay - Square for WordPress plugin presents a critical cross-site request forgery vulnerability that affects versions up to and including 3.2.0. This vulnerability stems from inadequate nonce validation within the wpep_download_transaction_in_excel() function, creating a significant security gap that adversaries can exploit to manipulate the plugin's functionality. The flaw specifically targets the authentication and authorization mechanisms that should prevent unauthorized operations within the WordPress administrative environment, fundamentally undermining the security model that protects sensitive transaction data.
The technical implementation of this vulnerability allows attackers to craft malicious requests that bypass the normal security checks typically enforced by WordPress. When an administrator visits a malicious website or clicks on a crafted link, the forged request can trigger the transaction download functionality without proper verification of the administrator's intent. This represents a classic csrf attack vector where the attacker leverages the administrator's authenticated session to perform unauthorized actions. The vulnerability exists because the plugin fails to validate the nonce parameter that should be present in all administrative requests to ensure that the action originates from a legitimate source within the WordPress environment.
The operational impact of this vulnerability extends beyond simple data exposure, as it provides attackers with access to potentially sensitive financial transaction records that could include customer payment information, transaction amounts, and other proprietary business data. An attacker who successfully exploits this vulnerability could download comprehensive transaction histories, potentially enabling further malicious activities such as financial fraud, identity theft, or targeted attacks against customers whose payment information is contained within the downloaded data. The unauthenticated nature of the attack means that no prior credentials are required, making the exploitation relatively straightforward and increasing the attack surface significantly.
This vulnerability aligns with CWE-352, which specifically addresses Cross-Site Request Forgery weaknesses in software applications. The implementation failure in nonce validation demonstrates a fundamental flaw in the plugin's security architecture, as proper csrf protection requires that all state-changing operations in web applications validate the authenticity of the request source. From an attack perspective, this vulnerability maps to several ATT&CK techniques including initial access through malicious links and privilege escalation by leveraging administrative privileges to access sensitive data. Organizations using this plugin should immediately implement mitigations including updating to the patched version, implementing additional security layers such as web application firewalls, and monitoring for suspicious administrative activities that might indicate exploitation attempts. The vulnerability also underscores the importance of proper input validation and authentication checks in WordPress plugins, particularly those handling financial data, as outlined in various security best practices and compliance frameworks.