CVE-2016-10802 in cPanel
Summary
by MITRE
cPanel before 58.0.4 allows code execution in the context of other user accounts through the PHP CGI handler (SEC-142).
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Analysis
by VulDB Data Team • 07/22/2020
The vulnerability identified as CVE-2016-10802 affects cPanel versions prior to 58.0.4 and represents a critical security flaw in the PHP CGI handler implementation. This vulnerability enables malicious actors to execute arbitrary code within the context of other user accounts on the same server, effectively bypassing the standard isolation mechanisms that separate user environments. The issue stems from improper handling of PHP execution contexts within the cPanel interface, particularly when utilizing the CGI handler for PHP processing. The vulnerability specifically targets the configuration and execution flow of PHP scripts when accessed through cPanel's web interface, creating an opportunity for privilege escalation and cross-account code execution.
The technical flaw manifests in how cPanel processes PHP requests through the CGI handler, where insufficient input validation and context isolation allow attackers to manipulate the execution environment. When a user submits PHP code through the CGI handler, the system fails to properly validate or sanitize the input parameters, enabling an attacker to inject malicious code that gets executed within the context of another user's account. This represents a classic privilege escalation vulnerability where the attacker can leverage their access to one account to execute code with the privileges and permissions of another user. The vulnerability operates at the application layer and can be exploited through web-based interfaces, making it particularly dangerous in shared hosting environments where multiple users operate on the same server infrastructure.
The operational impact of this vulnerability is severe and far-reaching within cPanel environments, particularly in shared hosting scenarios where multiple customers share the same server resources. An attacker who successfully exploits this vulnerability can gain access to other users' files, databases, and system resources, potentially leading to complete compromise of the affected server. The cross-account execution capability means that even if an attacker initially gains access through a low-privilege account, they can escalate their access to perform actions that would normally be restricted to higher-privileged users. This vulnerability can facilitate data theft, service disruption, and unauthorized access to sensitive customer information, making it a significant concern for hosting providers and organizations relying on cPanel for their web hosting infrastructure. The impact extends beyond individual accounts to potentially compromise the entire hosting environment and affect all users on the same server.
Mitigation strategies for CVE-2016-10802 should focus on immediate patching of cPanel installations to version 58.0.4 or later, which contains the necessary fixes for the PHP CGI handler vulnerability. Organizations should implement network segmentation and access controls to limit exposure of cPanel interfaces to trusted networks only, reducing the attack surface for potential exploitation attempts. Additional defensive measures include monitoring for unusual PHP execution patterns, implementing strict input validation for all web-based PHP requests, and regularly auditing user permissions and account configurations. Security professionals should also consider implementing web application firewalls to detect and block suspicious requests targeting the PHP CGI handler. The vulnerability aligns with CWE-77 and CWE-20 categories related to command injection and input validation failures, and maps to ATT&CK techniques involving privilege escalation and execution through web interfaces. Regular security assessments and vulnerability scanning should be conducted to ensure that similar vulnerabilities are not present in other components of the hosting infrastructure.