CVE-2024-9435 in Employee Shift Scheduling Plugin
Summary
by MITRE • 10/04/2024
The ShiftController Employee Shift Scheduling plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via URL keys in all versions up to, and including, 4.9.66 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link.
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Analysis
by VulDB Data Team • 03/08/2025
The ShiftController Employee Shift Scheduling plugin for WordPress represents a critical security vulnerability that affects versions up to and including 4.9.66. This vulnerability manifests as a reflected cross-site scripting flaw that exploits insufficient input sanitization and output escaping mechanisms within the plugin's codebase. The flaw occurs when user-supplied data from URL parameters is not properly validated or escaped before being rendered in web pages, creating an attack surface that can be exploited by malicious actors without requiring authentication credentials. The vulnerability specifically targets the plugin's handling of URL keys, which are commonly used for various administrative functions and user interactions within the scheduling system.
The technical implementation of this vulnerability stems from the plugin's failure to properly sanitize user input received through URL parameters. When an attacker crafts a malicious URL containing script code within the vulnerable parameters, the plugin processes this input without adequate filtering mechanisms. The unsanitized data is then reflected back to the user's browser in the response, executing the injected script in the context of the victim's session. This behavior aligns with CWE-79, which defines cross-site scripting as the improper handling of input data that allows attackers to inject client-side scripts into web applications. The vulnerability's impact is amplified by the fact that it requires no authentication, making it particularly dangerous for widely used plugins where users may inadvertently click on malicious links shared through various communication channels.
The operational implications of this vulnerability extend beyond simple script execution, as it provides attackers with the capability to perform various malicious activities within the context of authenticated users. Attackers can leverage this vulnerability to steal session cookies, redirect users to malicious websites, deface the scheduling interface, or even escalate privileges within the WordPress environment. The reflected nature of the attack means that successful exploitation requires social engineering to convince victims to click on malicious links, but once clicked, the script executes automatically in the victim's browser. This makes the vulnerability particularly dangerous in environments where multiple users interact with the scheduling system, as it could compromise the security of entire user bases through a single malicious link.
Mitigation strategies for this vulnerability should prioritize immediate remediation through plugin updates to versions that address the input sanitization and output escaping deficiencies. Organizations should implement comprehensive monitoring of their WordPress installations to identify any instances of the vulnerable plugin version and ensure all users are upgraded promptly. Network-based security controls such as web application firewalls can provide additional protection by filtering suspicious URL parameters before they reach the vulnerable plugin. The ATT&CK framework categorizes this type of vulnerability under T1059.007 for scripting languages, highlighting the need for proper input validation and output encoding practices. Additionally, administrators should conduct regular security audits of their WordPress plugins to identify and remediate similar vulnerabilities, while implementing proper access controls and user education programs to reduce the risk of successful social engineering attacks that exploit this flaw.