CVE-2021-4420 in Sell Media Plugin
Summary
by MITRE • 07/12/2023
The Sell Media plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 2.5.5. This is due to missing or incorrect nonce validation on the sell_media_process() function. This makes it possible for unauthenticated attackers to sell media paypal orders 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 Sell Media plugin for WordPress represents a popular solution for creating digital storefronts within WordPress environments, enabling users to sell various forms of media content including images, videos, and documents. This plugin integrates with PayPal payment processing systems to facilitate transactions, making it a critical component in many WordPress-based e-commerce setups. The vulnerability identified in versions up to and including 2.5.5 affects the core functionality of the plugin's payment processing mechanism, specifically targeting the sell_media_process() function that handles order validation and transaction completion.
The technical flaw stems from inadequate nonce validation within the sell_media_process() function, which serves as a cryptographic token designed to prevent cross-site request forgery attacks. Nonces are essential security mechanisms that ensure requests originate from legitimate sources within the same session, typically generated by WordPress and validated before processing sensitive operations. In this case, the absence or improper implementation of nonce verification creates a pathway for malicious actors to craft forged requests that appear to come from authenticated administrators. The vulnerability allows attackers to manipulate the payment processing flow without requiring authentication, as the system fails to validate the authenticity of incoming requests through proper nonce checks.
The operational impact of this vulnerability extends beyond simple unauthorized transactions, potentially enabling attackers to manipulate payment orders, redirect funds, or create fraudulent purchases within the plugin's payment processing framework. Since the vulnerability affects unauthenticated attackers, it requires minimal prerequisites for exploitation, typically involving social engineering tactics to convince administrators to click on malicious links. This makes the attack vector particularly dangerous in environments where administrators frequently interact with external links or where phishing campaigns target WordPress administrators. The consequences could include financial losses, compromised customer data, and potential reputational damage to businesses relying on the plugin for their digital commerce operations.
Security practitioners should implement immediate mitigations including updating to the patched version of the Sell Media plugin, which addresses the nonce validation issue by properly implementing WordPress security protocols. The vulnerability aligns with CWE-352, which specifically addresses Cross-Site Request Forgery weaknesses in web applications. From an ATT&CK framework perspective, this represents a technique that could be leveraged in the initial access phase through social engineering, followed by privilege escalation or lateral movement within the affected WordPress environment. Organizations should also consider implementing additional monitoring for suspicious payment processing activities and reviewing plugin security practices to prevent similar vulnerabilities in other third-party components within their WordPress infrastructure.