CVE-2018-16164 in Event Calendar WD
Summary
by MITRE
Cross-site scripting vulnerability in Event Calendar WD version 1.1.21 and earlier allows remote authenticated attackers to inject arbitrary web script or HTML via unspecified vectors.
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Analysis
by VulDB Data Team • 06/23/2023
The vulnerability identified as CVE-2018-16164 represents a cross-site scripting flaw within the Event Calendar WD plugin version 1.1.21 and earlier, constituting a critical security weakness that exposes WordPress installations to potential exploitation. This vulnerability specifically affects authenticated users who possess the ability to create or modify calendar events, creating a significant attack surface for malicious actors seeking to compromise user sessions or execute unauthorized actions. The flaw resides in the plugin's handling of user-supplied input without proper sanitization or output encoding, enabling attackers to inject malicious scripts that execute within the context of other users' browsers.
The technical implementation of this vulnerability stems from insufficient input validation and output escaping mechanisms within the Event Calendar WD plugin's event creation and modification interfaces. Attackers can leverage this weakness by crafting malicious payloads containing script code within event titles, descriptions, or other editable fields that are subsequently rendered on calendar pages without proper HTML escaping. This allows for the execution of arbitrary JavaScript code in victims' browsers, potentially leading to session hijacking, credential theft, or the execution of unauthorized administrative actions. The vulnerability operates under CWE-79 which categorizes cross-site scripting as a weakness where untrusted data is improperly incorporated into web pages, and aligns with ATT&CK technique T1059.007 for scripting languages.
The operational impact of this vulnerability extends beyond simple script injection, as authenticated attackers can exploit it to escalate privileges within the WordPress environment. When users with appropriate permissions view infected calendar entries, their browsers execute the malicious code, potentially allowing attackers to steal session cookies, modify calendar data, or redirect users to malicious sites. The vulnerability affects all users who can create or edit events, making it particularly dangerous in multi-user environments where administrators or editors might inadvertently trigger the execution of malicious code. Organizations running vulnerable versions of Event Calendar WD face significant risk of persistent security breaches, as the malicious scripts can remain active until the infected calendar entries are removed or the plugin is updated.
Mitigation strategies for CVE-2018-16164 require immediate action including updating to Event Calendar WD version 1.1.22 or later, which contains the necessary patches to address the XSS vulnerability. System administrators should also implement additional defensive measures such as regular security audits of installed plugins, implementing content security policies to limit script execution, and monitoring user activities for suspicious calendar modifications. Organizations should consider implementing web application firewalls to detect and block potential XSS payloads, while also establishing security awareness training for users who can create calendar entries. The vulnerability demonstrates the importance of proper input sanitization and output encoding practices, with remediation efforts focusing on ensuring all user-supplied data is properly escaped before being rendered in web contexts. Security teams should also conduct vulnerability assessments to identify other potentially affected plugins and ensure comprehensive protection across their WordPress environments.