CVE-2017-15812 in Easy Appointments Plugin
Summary
by MITRE
The Easy Appointments plugin before 1.12.0 for WordPress has XSS via a Settings values in the admin panel.
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Analysis
by VulDB Data Team • 02/06/2025
The Easy Appointments plugin for WordPress contains a cross-site scripting vulnerability that affects versions prior to 1.12.0, specifically within the admin panel settings functionality. This vulnerability stems from inadequate input validation and output sanitization of user-supplied data entered into the plugin's configuration parameters. The flaw allows authenticated attackers with administrative privileges to inject malicious scripts into the plugin's settings interface, which then executes in the context of other administrators or users who view the affected pages. The vulnerability exists because the plugin fails to properly escape and validate data before rendering it back to the user interface, creating an avenue for persistent XSS attacks.
The technical implementation of this vulnerability involves the plugin's handling of user inputs within the settings management system. When administrators modify plugin configurations through the WordPress admin panel, the input values are stored without proper sanitization measures. The stored data is then retrieved and displayed in subsequent administrative interfaces without appropriate HTML escaping or context-aware output encoding. This creates a classic persistent cross-site scripting scenario where malicious payloads can be stored in the database and executed whenever the affected settings page is accessed. The vulnerability is particularly dangerous because it operates within the privileged administrative context of WordPress, potentially allowing attackers to escalate their privileges or extract sensitive information from the compromised system.
From an operational impact perspective, this vulnerability represents a significant security risk for WordPress installations using the Easy Appointments plugin. The attacker can leverage this vulnerability to execute arbitrary JavaScript code in the browser of authenticated users, potentially leading to session hijacking, data theft, or further system compromise. The persistent nature of the vulnerability means that once exploited, the malicious code will continue to execute for all users who access the affected administrative pages until the plugin is updated or the malicious input is removed. This makes the vulnerability particularly dangerous in multi-user environments where administrators frequently access plugin settings and where the compromised system may contain sensitive customer appointment data.
Mitigation strategies for this vulnerability include immediate patching to version 1.12.0 or later, which addresses the input validation and output sanitization issues. Organizations should also implement additional security measures such as regular security audits of WordPress plugins, implementation of content security policies to limit script execution, and monitoring of administrative interfaces for suspicious activity. The vulnerability aligns with CWE-79, which describes cross-site scripting flaws, and represents a typical example of how insufficient input validation can lead to persistent XSS attacks. From an ATT&CK framework perspective, this vulnerability maps to technique T1059.007 for command and scripting interpreter and T1566 for credential access through social engineering, as attackers could use the XSS to capture administrative credentials or manipulate the system's functionality. Organizations should also consider implementing web application firewalls to detect and block malicious payloads, and establish processes for regular plugin vulnerability assessments to prevent similar issues in other components of their WordPress installations.