CVE-2015-9472 in incoming-links Plugin
Summary
by MITRE
The incoming-links plugin before 0.9.10b for WordPress has referrers.php XSS via the Referer HTTP header.
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Analysis
by VulDB Data Team • 01/07/2024
The vulnerability identified as CVE-2015-9472 affects the incoming-links plugin for WordPress, specifically targeting versions prior to 0.9.10b. This security flaw exists within the referrers.php component of the plugin, which is designed to track and display incoming links to a WordPress site. The issue manifests as a cross-site scripting vulnerability that can be exploited through manipulation of the HTTP Referer header, making it particularly dangerous as it leverages a standard HTTP header that most web applications process automatically.
The technical implementation of this vulnerability stems from inadequate input validation and output sanitization within the plugin's referrers.php file. When the plugin processes incoming HTTP requests, it fails to properly sanitize the Referer header before displaying it on the plugin's administrative interface. This allows an attacker to inject malicious JavaScript code into the Referer header, which then gets executed when the administrator views the referrer information within the WordPress admin panel. The vulnerability directly maps to CWE-79, which describes cross-site scripting flaws where untrusted data is improperly incorporated into web pages without proper validation or encoding.
The operational impact of this vulnerability extends beyond simple script execution, as it creates a potential vector for more sophisticated attacks. An attacker who can manipulate the Referer header can execute arbitrary JavaScript code in the context of the administrator's browser session, potentially leading to session hijacking, privilege escalation, or data exfiltration. The vulnerability is particularly concerning in environments where administrators regularly monitor incoming link references, as simply viewing the plugin's interface could trigger the malicious script execution. This attack vector aligns with ATT&CK technique T1566, specifically targeting the manipulation of web application inputs to achieve unauthorized code execution.
The exploitation of this vulnerability requires minimal prerequisites, as it only requires the ability to influence HTTP headers during web requests to the WordPress site. Attackers can craft malicious requests with specially formatted Referer headers that contain JavaScript payloads, which will execute when the administrator views the incoming links information. The vulnerability's persistence is limited to the duration of the browser session, but the potential for privilege escalation makes it particularly dangerous. Organizations should note that this vulnerability affects WordPress plugin ecosystems and demonstrates the importance of maintaining updated third-party components, as the issue was resolved in version 0.9.10b of the plugin. The vulnerability highlights the critical need for proper input validation and output encoding practices, especially when dealing with user-supplied data in web applications, and emphasizes the necessity of implementing defense-in-depth strategies that include regular security assessments of all installed plugins and themes.