CVE-2016-10840 in cPanel
Summary
by MITRE
cPanel before 11.54.0.4 allows arbitrary code execution during locale duplication (SEC-72).
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Analysis
by VulDB Data Team • 11/20/2023
The vulnerability identified as CVE-2016-10840 represents a critical arbitrary code execution flaw within cPanel software versions prior to 11.54.0.4. This security weakness specifically manifests during the locale duplication process, which is a routine administrative function used to create copies of language localization files for different regions and languages. The issue stems from inadequate input validation and sanitization mechanisms within the locale duplication functionality, creating a pathway for malicious actors to inject and execute arbitrary code on affected systems. The vulnerability is particularly concerning because it allows remote code execution without requiring authentication, making it accessible to attackers who can exploit it from outside the network perimeter. The flaw is categorized under CWE-94, which describes "Improper Control of Generation of Code ('Code Injection')" and aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: Python" and T1059.001 for "Command and Scripting Interpreter: PowerShell," as the exploitation typically involves code injection into the system's scripting environments.
The technical implementation of this vulnerability involves the improper handling of user-supplied data during locale duplication operations. When administrators or attackers attempt to duplicate locale files, the system fails to properly validate or sanitize the input parameters, allowing malicious payloads to be processed and executed within the context of the cPanel application. This occurs because the software does not adequately filter or escape special characters and command sequences that could be interpreted by the underlying operating system or scripting engine. The lack of proper access controls and input sanitization creates a direct code execution pathway that bypasses normal security boundaries. The vulnerability's impact is amplified by the fact that cPanel is widely deployed across hosting environments and web servers, making it a prime target for automated exploitation campaigns. The flaw essentially allows an attacker to execute arbitrary commands with the privileges of the cPanel process, which typically runs with elevated system permissions.
The operational impact of CVE-2016-10840 extends beyond simple code execution to encompass complete system compromise and potential data breaches. Successful exploitation can result in unauthorized access to sensitive customer data, server control, and the ability to establish persistent backdoors within the compromised environment. Attackers can leverage this vulnerability to install malware, exfiltrate information, or use the compromised server as a launchpad for further attacks against other systems within the network. The vulnerability's classification as a remote code execution flaw means that attackers do not need physical access or valid credentials to exploit the system, making it particularly dangerous in shared hosting environments where multiple customers may be affected. Organizations using vulnerable cPanel versions face significant risk of service disruption, regulatory compliance violations, and potential legal consequences due to data exposure. The vulnerability's presence in widely used hosting software creates a cascading effect where a single compromised server can lead to broader security incidents across interconnected systems.
Mitigation strategies for CVE-2016-10840 primarily focus on immediate software updates and administrative controls. The most effective remediation involves upgrading to cPanel version 11.54.0.4 or later, which includes patches specifically addressing the locale duplication vulnerability. Organizations should also implement network segmentation and access controls to limit exposure, ensuring that only authorized personnel can perform locale duplication operations. Additional protective measures include monitoring system logs for suspicious activities related to locale handling, implementing intrusion detection systems, and conducting regular vulnerability assessments of hosting infrastructure. Security administrators should also consider disabling unnecessary locale duplication features when not required, and establishing strict input validation policies for all administrative functions. The vulnerability's characteristics align with ATT&CK technique T1566.001 for "Phishing: Spearphishing Attachment" and T1078.004 for "Valid Accounts: Cloud Accounts," as attackers may exploit this vulnerability to gain initial access or escalate privileges within cloud hosting environments. Organizations should also review their incident response procedures to ensure preparedness for potential exploitation of this type of vulnerability.