CVE-2016-10843 in cPanel
Summary
by MITRE
cPanel before 11.54.0.4 allows code execution in the context of shared users via JSON-API (SEC-76).
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Analysis
by VulDB Data Team • 11/20/2023
The vulnerability identified as CVE-2016-10843 represents a critical code execution flaw within cPanel versions prior to 11.54.0.4, specifically affecting the JSON-API component that governs shared user contexts. This vulnerability stems from inadequate input validation and sanitization mechanisms within the application's API handling subsystem, creating a pathway for malicious actors to execute arbitrary code with the privileges of shared users. The JSON-API interface serves as a critical communication channel between administrative tools and the cPanel backend, making it a prime target for exploitation. Attackers can leverage this vulnerability by crafting malicious API requests that bypass normal access controls and validation checks, ultimately allowing them to execute commands on the target system.
The technical exploitation of this vulnerability occurs through the improper handling of user-supplied data within the JSON-API framework. When shared users submit requests through the API, the system fails to adequately validate or sanitize the input parameters before processing them. This lack of proper sanitization creates a code injection vector where attackers can inject malicious commands that get executed within the context of the shared user account. The vulnerability specifically targets the shared user privilege model where multiple users may share the same hosting environment, potentially enabling attackers to escalate their privileges or compromise other user accounts. The flaw resides in the API's parameter handling logic, which does not properly distinguish between legitimate user inputs and potentially malicious payloads, making it susceptible to exploitation through carefully crafted JSON requests.
The operational impact of CVE-2016-10843 extends beyond simple unauthorized code execution, as it can lead to complete system compromise when exploited effectively. Shared hosting environments are particularly vulnerable due to the multi-tenant nature of the infrastructure, where a single compromised account can potentially affect other users on the same server. Attackers can leverage this vulnerability to establish persistent backdoors, exfiltrate sensitive data, modify system configurations, or even escalate privileges to root access depending on the underlying system architecture. The vulnerability affects organizations that rely on cPanel for hosting management, particularly those with shared hosting environments where multiple customers share the same physical or virtual infrastructure. This creates a significant risk for web hosting providers, e-commerce platforms, and any organization using shared hosting services that have not updated to the patched version.
Mitigation strategies for CVE-2016-10843 primarily involve immediate application of the vendor-provided security patch released in cPanel version 11.54.0.4, which addresses the input validation and sanitization issues within the JSON-API component. Organizations should implement comprehensive monitoring of API access logs to detect suspicious activities that may indicate exploitation attempts, including unusual request patterns or unauthorized command executions. Network-level security controls such as API firewalls and intrusion detection systems should be configured to filter malicious requests before they reach the cPanel application. Additionally, organizations should conduct thorough security assessments of their hosting infrastructure, implementing least privilege access controls and regular security audits to identify potential vulnerabilities. The remediation process should include updating all cPanel installations to the latest stable version, disabling unnecessary API endpoints, and implementing strict input validation policies. This vulnerability aligns with CWE-74 and CWE-79 categories related to injection flaws and cross-site scripting respectively, while also mapping to ATT&CK techniques involving command and script execution and privilege escalation.