CVE-2016-10784 in cPanel
Summary
by MITRE
cPanel before 60.0.25 allows self XSS in the alias upload interface (SEC-184).
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Analysis
by VulDB Data Team • 07/21/2020
The vulnerability identified as CVE-2016-10784 represents a critical self-cross-site scripting flaw discovered in cPanel versions prior to 60.0.25. This security weakness specifically affects the alias upload interface within the cPanel administrative control panel, which is widely used by hosting providers and system administrators to manage domain aliases and email forwarding settings. The vulnerability stems from insufficient input validation and output sanitization mechanisms within the web application's user interface, creating an exploitable condition where maliciously crafted input can be executed in the context of the authenticated user's browser session. This type of vulnerability falls under the CWE-79 category of Cross-Site Scripting, specifically classified as self-XSS since the attack vector targets the application's own users rather than external parties.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious payload within the alias upload interface and submits it through the vulnerable form fields. The application fails to properly sanitize or escape user-supplied data before rendering it back to the browser, allowing the malicious script to execute in the context of the authenticated user's session. This creates a persistent threat where any user with access to the alias upload functionality can be tricked into executing malicious code, potentially leading to session hijacking, privilege escalation, or data exfiltration. The vulnerability is particularly concerning because cPanel serves as a critical administrative interface for hosting environments, making it an attractive target for attackers seeking to compromise hosting infrastructure and gain unauthorized access to multiple client accounts.
The operational impact of this vulnerability extends beyond individual user sessions to potentially compromise entire hosting environments. When attackers exploit this self-XSS vulnerability, they can manipulate the alias upload interface to execute malicious scripts that may redirect users to phishing sites, steal session cookies, or inject additional malicious code into the hosting environment. The attack surface is amplified because cPanel administrators often have elevated privileges and access to sensitive customer data, making successful exploitation a significant threat to data integrity and confidentiality. This vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter, specifically targeting the web application layer through browser-based scripting attacks. The vulnerability also maps to ATT&CK technique T1566.001 for Phishing, as attackers can leverage the self-XSS condition to craft convincing phishing attacks that appear legitimate within the cPanel interface.
Mitigation strategies for CVE-2016-10784 require immediate implementation of the vendor-provided security patch, which updates the alias upload interface to properly sanitize and escape user input before rendering it in the browser. Organizations should also implement additional security controls such as input validation at multiple layers, output encoding for all dynamic content, and regular security audits of web application interfaces. Network-based protections like web application firewalls can provide additional defense-in-depth, though they are not a substitute for proper code-level fixes. Security monitoring should include detection of suspicious upload activities and anomalous user behavior within the cPanel interface. The vulnerability demonstrates the critical importance of maintaining up-to-date software versions and implementing robust input validation practices, as this type of self-XSS vulnerability can persist in environments where patch management processes are inadequate or delayed. Regular security training for administrators and developers on secure coding practices is essential to prevent similar vulnerabilities from being introduced in future releases.