CVE-2015-9527 in Simple Shipping Extension
Summary
by MITRE
The Easy Digital Downloads (EDD) Simple Shipping extension for WordPress, as used with EDD 1.8.x before 1.8.7, 1.9.x before 1.9.10, 2.0.x before 2.0.5, 2.1.x before 2.1.11, 2.2.x before 2.2.9, and 2.3.x before 2.3.7, has XSS because add_query_arg is misused.
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Analysis
by VulDB Data Team • 02/07/2025
The vulnerability identified as CVE-2015-9527 affects the Easy Digital Downloads Simple Shipping extension for WordPress, representing a cross-site scripting weakness that has persisted across multiple versions of the EDD plugin. This issue specifically manifests in versions prior to the mentioned secure releases, creating a persistent security risk for WordPress sites utilizing this e-commerce extension. The vulnerability stems from improper handling of user input within the add_query_arg function, which is a core WordPress utility for managing URL parameters and query strings. The flaw allows malicious actors to inject malicious scripts into URLs that are subsequently processed by the extension, potentially compromising user sessions and data integrity.
The technical implementation of this vulnerability involves the misuse of WordPress's add_query_arg function, which is designed to safely append query parameters to URLs while maintaining proper encoding and sanitization. However, in the affected versions of the Simple Shipping extension, this function is being called in a manner that fails to properly sanitize user-supplied input before incorporating it into URL parameters. This improper usage creates an environment where attacker-controlled data can be injected into query strings without adequate validation or encoding, enabling the execution of malicious scripts when these URLs are processed or displayed to users. The vulnerability is classified as a classic XSS flaw under CWE-79, which specifically addresses cross-site scripting vulnerabilities in web applications.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable attackers to perform session hijacking, steal sensitive user information, manipulate the functionality of the e-commerce platform, and potentially gain unauthorized access to administrative functions. When users visit pages containing maliciously crafted URLs, the injected scripts execute in their browsers, potentially leading to unauthorized transactions, data theft, or complete compromise of user accounts. The vulnerability affects not only individual users but also the broader WordPress ecosystem, as it demonstrates a pattern of insecure coding practices within the Simple Shipping extension that could be exploited across various WordPress installations. This type of vulnerability aligns with ATT&CK technique T1566, which covers the exploitation of web application vulnerabilities to gain unauthorized access to systems.
Mitigation strategies for this vulnerability require immediate patching of the affected EDD Simple Shipping extension to versions that properly sanitize query parameters before incorporating them into URLs. Organizations should also implement additional security measures including input validation, output encoding, and regular security audits of third-party plugins. The WordPress security community recommends maintaining updated versions of all plugins and themes, implementing web application firewalls, and monitoring for suspicious URL patterns that may indicate exploitation attempts. Additionally, administrators should consider implementing content security policies to prevent unauthorized script execution and establish regular vulnerability scanning procedures to identify similar issues in other components of their WordPress installations. The vulnerability serves as a reminder of the critical importance of proper input sanitization and the potential consequences of relying on insecure coding practices in web applications.