CVE-2012-6527 in My-calendar
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the My Calendar plugin before 1.10.2 for WordPress allows remote attackers to inject arbitrary web script or HTML via the PATH_INFO.
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Analysis
by VulDB Data Team • 12/21/2021
The CVE-2012-6527 vulnerability represents a critical cross-site scripting flaw in the My Calendar WordPress plugin affecting versions prior to 1.10.2. This vulnerability resides in the plugin's handling of PATH_INFO parameters, creating an avenue for remote attackers to execute malicious web scripts or HTML code within the context of affected websites. The issue stems from inadequate input validation and output sanitization mechanisms within the plugin's codebase, specifically when processing URL path information that is typically used for routing requests within web applications. The vulnerability manifests when user-supplied data from PATH_INFO is directly incorporated into web page responses without proper sanitization, enabling attackers to inject malicious payloads that can persist and execute against unsuspecting users.
From a technical perspective, the vulnerability operates through the exploitation of improper parameter handling within the My Calendar plugin's request processing logic. When the plugin processes requests containing PATH_INFO components, it fails to adequately validate or sanitize the input data before rendering it in web responses. This creates a classic XSS attack vector where malicious actors can craft URLs containing script tags or other HTML content that gets executed in the browsers of users visiting affected pages. The vulnerability is particularly concerning because it leverages the PATH_INFO parameter which is often used by web servers for routing and can contain arbitrary user input that is not properly filtered by the application layer. This weakness aligns with CWE-79, which specifically addresses cross-site scripting vulnerabilities in web applications, and represents a failure to implement proper input validation and output encoding practices that are fundamental to secure web development.
The operational impact of CVE-2012-6527 extends beyond simple script injection, potentially allowing attackers to hijack user sessions, steal sensitive information, or redirect users to malicious websites. When exploited, the vulnerability can enable attackers to perform actions such as stealing cookies, modifying calendar events, or even gaining administrative access to compromised WordPress installations. The attack surface is significant given that My Calendar is a widely used plugin, making numerous WordPress sites vulnerable to this type of exploitation. The vulnerability's remote nature means that attackers can exploit it without requiring local access to the target system, and the persistence of the XSS payload means that once a user visits an infected page, they become a vector for further attacks. This aligns with ATT&CK technique T1566, which covers social engineering tactics involving malicious payloads delivered through web-based attacks, and T1071.001, which addresses application layer protocol usage for command and control communications.
Mitigation strategies for CVE-2012-6527 primarily focus on immediate patching of the My Calendar plugin to version 1.10.2 or later, which contains the necessary fixes for input validation and sanitization. System administrators should also implement additional protective measures including web application firewalls that can detect and block suspicious PATH_INFO patterns, input validation rules that restrict potentially dangerous characters in URL parameters, and output encoding mechanisms that ensure all user-supplied data is properly escaped before rendering in web pages. Regular security auditing of WordPress plugins and themes remains crucial for identifying similar vulnerabilities, while implementing Content Security Policy headers can provide additional defense-in-depth against XSS attacks. Organizations should also consider implementing automated monitoring solutions that can detect unusual patterns in web traffic or unauthorized modifications to calendar data that might indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date third-party components in web applications and the necessity of following secure coding practices that prevent injection vulnerabilities through proper input validation and output sanitization.