CVE-2016-10789 in cPanel
Summary
by MITRE
cPanel before 60.0.25 allows code execution via the cpsrvd 403 error response handler (SEC-191).
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Analysis
by VulDB Data Team • 07/21/2020
The vulnerability identified as CVE-2016-10789 affects cPanel versions prior to 60.0.25 and represents a critical code execution flaw within the cpsrvd web server component. This vulnerability specifically targets the 403 error response handler mechanism, which is responsible for managing unauthorized access attempts to the cPanel interface. The flaw allows attackers to inject and execute arbitrary code on vulnerable systems through carefully crafted requests that trigger the error handling process. The vulnerability stems from insufficient input validation and sanitization within the error response generation logic, creating a pathway for remote code execution that bypasses normal authentication and authorization mechanisms.
The technical implementation of this vulnerability involves the manipulation of HTTP request parameters that are processed by the cpsrvd service when generating 403 error responses. Attackers can exploit this by sending specially crafted requests that cause the system to include user-controllable data in the error response generation process. This occurs due to improper handling of user input within the error response handler, which fails to properly escape or validate data before incorporating it into the response. The vulnerability is particularly dangerous because it allows execution of code with the privileges of the cpsrvd process, which typically runs with high system privileges. This flaw is classified under CWE-94, which describes "Improper Control of Generation of Code ('Code Injection')" and aligns with ATT&CK technique T1059.001 for command and script injection.
The operational impact of this vulnerability is severe and far-reaching for organizations using affected cPanel versions. Successful exploitation can result in complete system compromise, allowing attackers to establish persistent backdoors, exfiltrate sensitive data, deploy additional malware, or use the compromised system as a launch point for further attacks within the network. The vulnerability affects not just individual user accounts but potentially entire hosting environments, as cPanel administrators often have elevated privileges and control over multiple user accounts and server resources. Organizations may experience data breaches, service disruption, and compliance violations that could result in significant financial and reputational damage. The vulnerability's remote exploitation capability means that attackers can target systems without requiring physical access or prior authentication, making it particularly attractive for automated attack campaigns.
Mitigation strategies for this vulnerability primarily involve immediate upgrading to cPanel version 60.0.25 or later, which contains the necessary patches to address the code injection flaw in the error response handler. Organizations should also implement network-level protections such as firewall rules that restrict access to cPanel ports and services, particularly in environments where direct internet access to the control panel is not required. Additional defensive measures include monitoring for unusual error response patterns, implementing web application firewalls to detect and block malicious payloads, and conducting thorough security audits of the cPanel installation to identify any potential exploitation attempts. Security teams should also review access controls and implement principle of least privilege configurations to minimize the impact if exploitation occurs. Regular vulnerability scanning and penetration testing should be conducted to identify similar issues within the broader hosting infrastructure and ensure comprehensive protection against related attack vectors.