CVE-2018-5671 in booking-calendar Plugin
Summary
by MITRE
An issue was discovered in the booking-calendar plugin 2.1.7 for WordPress. XSS exists via the wp-admin/admin.php extra_field1[items][field_item1][price_percent] parameter.
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Analysis
by VulDB Data Team • 12/23/2019
The vulnerability identified as CVE-2018-5671 represents a cross-site scripting flaw within the booking-calendar plugin version 2.1.7 for WordPress platforms. This security weakness manifests through the wp-admin/admin.php endpoint where the extra_field1[items][field_item1][price_percent] parameter fails to properly sanitize user input, creating an avenue for malicious actors to inject arbitrary web scripts into the administrative interface. The flaw resides in the plugin's handling of form data submitted through the WordPress admin dashboard, specifically when processing booking calendar configuration parameters that control pricing structures and field definitions.
The technical implementation of this vulnerability stems from insufficient input validation and output escaping mechanisms within the plugin's backend processing logic. When administrators navigate to the booking calendar settings page and interact with the price percentage configuration fields, the plugin fails to adequately filter or encode user-supplied data before rendering it back to the browser. This allows attackers to craft malicious payloads that exploit the trust relationship between the authenticated administrator and the WordPress admin interface, enabling the execution of arbitrary JavaScript code within the context of the admin session. The vulnerability specifically targets the parameter structure that manages percentage-based pricing calculations for calendar booking items, making it particularly dangerous for users who manage booking systems with sensitive pricing configurations.
The operational impact of this vulnerability extends beyond simple script injection, as it provides attackers with the capability to escalate privileges and potentially compromise the entire WordPress installation. An attacker who successfully exploits this XSS vulnerability can manipulate the booking calendar functionality to redirect users to malicious sites, steal administrative session cookies, or modify booking configurations to facilitate fraudulent transactions. The vulnerability is particularly concerning because it operates within the wp-admin context, meaning that successful exploitation requires only a single authenticated session, and the attacker can leverage this access to perform actions such as modifying booking rules, altering pricing structures, or even creating new booking items with malicious configurations. This type of vulnerability falls under CWE-79 which specifically addresses Cross-Site Scripting flaws, and aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: JavaScript, demonstrating how attackers can leverage web-based vulnerabilities to execute malicious code within the target environment.
Mitigation strategies for CVE-2018-5671 should prioritize immediate plugin updates to versions that address the XSS vulnerability through proper input sanitization and output encoding. System administrators should implement additional security measures including the use of Content Security Policy headers to limit script execution within the admin interface, regular monitoring of WordPress plugin directories for unauthorized modifications, and ensuring that only essential administrators have access to the booking calendar configuration settings. The vulnerability highlights the importance of proper input validation at multiple layers within web applications, as recommended by OWASP Top Ten security practices, and underscores the critical need for regular security audits of third-party WordPress plugins. Organizations should also consider implementing web application firewalls to detect and block malicious payloads targeting known XSS patterns, and establish incident response procedures for monitoring unauthorized changes to booking calendar configurations that could indicate exploitation attempts.