CVE-2016-10767 in cPanel
Summary
by MITRE
cPanel before 60.0.25 allows stored XSS in the WHM Repair Mailbox Permissions interface (SEC-159).
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Analysis
by VulDB Data Team • 07/20/2020
The vulnerability CVE-2016-10767 represents a stored cross-site scripting flaw within cPanel's WHM Repair Mailbox Permissions interface, affecting versions prior to 60.0.25. This security weakness resides in the web-based management interface of cPanel, which is widely deployed across hosting environments and serves as a critical administrative tool for system administrators managing multiple domains and user accounts. The flaw specifically targets the repair mailbox permissions functionality, which is used to correct email account access configurations and permissions within the hosting environment. The vulnerability classification aligns with CWE-79, which addresses Cross-Site Scripting flaws, and demonstrates how improper input validation can create persistent security risks within web applications. Attackers exploiting this vulnerability could inject malicious scripts into the application's interface through the repair mailbox permissions form, potentially affecting all users who interact with the affected functionality.
The technical implementation of this stored XSS vulnerability occurs when user-supplied input containing malicious script code is not properly sanitized or validated before being stored in the application's database and subsequently rendered within the web interface. In the context of the WHM Repair Mailbox Permissions interface, when administrators or users enter specific payload data into input fields, the application fails to adequately escape or filter special characters that could be interpreted as executable script code. This allows attackers to inject malicious JavaScript code that persists in the application's data storage and executes whenever the affected interface is accessed by other users. The vulnerability's persistence stems from the fact that the malicious content is stored server-side rather than being reflected in a single request, making it particularly dangerous as it can affect multiple users over extended periods without requiring repeated exploitation attempts.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to escalate privileges, steal session cookies, perform unauthorized actions within the cPanel environment, and potentially gain access to sensitive user data or system configurations. Given that cPanel serves as a critical management interface for hosting providers and their customers, successful exploitation could allow attackers to compromise entire hosting environments, manipulate email configurations, access user accounts, or even escalate to system-level privileges depending on the execution context. The attack surface is particularly concerning because WHM interfaces typically grant elevated privileges to system administrators, making successful exploitation potentially devastating for hosting environments. This vulnerability directly maps to ATT&CK technique T1059.007 for Command and Scripting Interpreter, as well as T1531 for Account Access Removal, since the stored nature of the vulnerability enables persistent access and manipulation of administrative functions.
Mitigation strategies for CVE-2016-10767 focus primarily on updating cPanel to version 60.0.25 or later, which contains the necessary patches to address the input validation flaws. Organizations should implement comprehensive patch management procedures to ensure all cPanel installations are updated promptly, particularly in environments where multiple hosting accounts or administrative interfaces are in use. Additional protective measures include implementing web application firewalls to monitor and filter suspicious input patterns, conducting regular security assessments of cPanel configurations, and establishing privileged access controls to limit exposure to the affected interface. Security monitoring should focus on identifying unusual administrative activities or unexpected script execution patterns within cPanel environments, while also ensuring proper input sanitization practices are implemented across all user-facing forms and data entry points. Organizations should also consider implementing principle of least privilege configurations for cPanel access and regularly audit administrative access logs to detect potential exploitation attempts. The vulnerability demonstrates the critical importance of input validation and output encoding in web applications, particularly in administrative interfaces where the potential for privilege escalation exists.