CVE-2015-9370 in Invoices Add-on for iThemes Exchange
Summary
by MITRE
Invoices Add-on for iThemes Exchange before 1.4.0 for WordPress has XSS via add_query_arg() and remove_query_arg().
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Analysis
by VulDB Data Team • 12/07/2023
The vulnerability identified as CVE-2015-9370 affects the Invoices Add-on for iThemes Exchange version prior to 1.4.0 within the WordPress ecosystem. This represents a cross-site scripting vulnerability that specifically targets the add_query_arg() and remove_query_arg() functions, which are fundamental components in WordPress plugin development for managing URL parameters. The flaw exists in how the plugin processes and sanitizes user-supplied input that gets incorporated into URL query strings, creating an attack surface where malicious actors can inject arbitrary JavaScript code.
The technical implementation of this vulnerability stems from inadequate input validation and output sanitization within the plugin's handling of query parameters. When users interact with the invoice functionality, the plugin utilizes WordPress's add_query_arg() and remove_query_arg() functions to manipulate URL parameters. However, these functions do not properly sanitize the input values before they are rendered in the browser context, allowing attackers to inject malicious payloads that execute in the context of other users' browsers. This particular weakness aligns with CWE-79, which specifically addresses cross-site scripting vulnerabilities, and demonstrates how improper handling of dynamic content can lead to severe security implications.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform various malicious activities including session hijacking, data theft, and privilege escalation within the affected WordPress environment. An attacker could craft malicious URLs containing script tags that would execute when legitimate users navigate to invoice-related pages, potentially stealing cookies, modifying user data, or redirecting users to phishing sites. The vulnerability affects not only the plugin's immediate functionality but also the broader WordPress installation, as successful exploitation could lead to complete compromise of user sessions and potentially the entire site if attackers can leverage additional weaknesses.
Mitigation strategies for this vulnerability require immediate patching of the affected plugin to version 1.4.0 or later, which includes proper sanitization of query parameters. Organizations should implement comprehensive input validation at multiple layers, ensuring that all user-supplied data passed through add_query_arg() and remove_query_arg() functions undergoes appropriate sanitization before being rendered in HTML contexts. Security measures should include regular security audits of WordPress plugins, implementation of content security policies to limit script execution, and monitoring for suspicious URL patterns. The remediation process must also involve verifying that all WordPress plugins and themes are updated to their latest versions, as outdated components often contain similar vulnerabilities. This vulnerability exemplifies the importance of following secure coding practices and adheres to ATT&CK technique T1059.001 for command and scripting interpreter, highlighting how insecure input handling can enable persistent threats within web applications.