CVE-2016-10837 in cPanel
Summary
by MITRE
cPanel before 11.54.0.4 allows arbitrary code execution because of an unsafe @INC path (SEC-46).
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Analysis
by VulDB Data Team • 11/20/2023
The vulnerability identified as CVE-2016-10837 represents a critical security flaw in cPanel software versions prior to 11.54.0.4 that enables arbitrary code execution through improper handling of the Perl @INC path. This issue stems from the software's insecure loading mechanism that does not properly validate or sanitize the library search path, creating an environment where malicious code can be executed with elevated privileges. The vulnerability specifically affects the core Perl interpreter functionality within cPanel's infrastructure, making it a fundamental weakness in the system's security architecture.
The technical implementation of this vulnerability occurs when cPanel processes Perl scripts that utilize the INC array, which is a special variable in Perl that contains the list of directories where the interpreter searches for modules and libraries. In affected versions, the software fails to properly sanitize or restrict the paths included in this array, allowing an attacker to manipulate the search path to include malicious directories. When Perl attempts to load modules, it will first search through the directories listed in INC, and if a malicious module exists in a directory that appears earlier in this path, it will be loaded instead of the legitimate module, effectively enabling code injection attacks.
The operational impact of this vulnerability extends far beyond simple code execution, as it provides attackers with the ability to gain unauthorized access to systems running vulnerable cPanel versions. The arbitrary code execution capability allows adversaries to perform a wide range of malicious activities including data exfiltration, system compromise, privilege escalation, and persistent backdoor installation. Since cPanel is widely used for web hosting management, this vulnerability affects numerous hosting providers and their customers, potentially leading to widespread system compromise across multiple domains. The vulnerability's severity is amplified by the fact that cPanel typically runs with elevated privileges, meaning successful exploitation could result in complete system compromise.
Security practitioners should recognize this vulnerability as a classic example of insecure library loading practices that aligns with CWE-427 and CWE-471 categories, representing weaknesses in the system's module resolution and path handling mechanisms. The issue also maps to ATT&CK technique T1059.007 for execution via Perl and T1068 for local privilege escalation, demonstrating how this vulnerability can be leveraged through multiple attack vectors within the broader threat landscape. Organizations should implement immediate mitigations including upgrading to cPanel version 11.54.0.4 or later, implementing proper input validation for Perl module loading, and monitoring system logs for suspicious module loading activities. Additionally, network segmentation and privilege separation measures should be enforced to limit the potential impact of successful exploitation, while regular security assessments should verify that the @INC path is properly configured to prevent malicious path injection attacks.