CVE-2016-10820 in cPanel
Summary
by MITRE
cPanel before 55.9999.141 allows daemons to access their controlling TTYs (SEC-31).
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Analysis
by VulDB Data Team • 11/20/2023
The vulnerability identified as CVE-2016-10820 affects cPanel versions prior to 55.9999.141 and relates to improper access control mechanisms within the daemon processes that manage system services. This security flaw allows daemon processes to access their controlling terminal devices, which represents a significant breach in the isolation mechanisms that should separate daemon operations from user interactive sessions. The issue stems from the lack of proper terminal access controls that would normally prevent background processes from directly accessing or manipulating the terminal sessions that control them.
This vulnerability falls under the category of improper access control as classified by CWE-284, where the daemon processes are able to access resources that they should not be permitted to access. The security implications arise from the fact that daemons typically operate with elevated privileges and are designed to run independently without direct user interaction. When these processes can access their controlling TTY, they potentially gain access to session information, input/output streams, and other terminal-related resources that could be exploited for privilege escalation or information disclosure attacks.
The operational impact of this vulnerability extends beyond simple access control violations, as it creates potential attack vectors for malicious actors who might attempt to manipulate daemon behavior through terminal interactions. The affected daemons could potentially be influenced to execute unintended operations or provide unauthorized access to system resources through their terminal connections. This scenario aligns with ATT&CK technique T1059 which covers command and script interpretation, as the compromised daemon access could enable execution of malicious commands through terminal manipulation.
The security advisory references SEC-31 which indicates that this vulnerability was recognized as a significant control flow issue within the cPanel security framework. The root cause involves insufficient separation between daemon processes and their controlling terminal sessions, allowing for potential privilege escalation and unauthorized access to system resources. This represents a fundamental flaw in the terminal session management architecture where daemon processes are not properly isolated from the terminal devices they control, creating opportunities for attackers to exploit this access relationship for malicious purposes.
The mitigation strategy for this vulnerability requires immediate deployment of cPanel version 55.9999.141 or later, which includes proper terminal access controls that prevent daemon processes from accessing their controlling TTYs. System administrators should also review current daemon configurations and ensure that proper access controls are implemented to prevent unauthorized terminal access. This remediation addresses the core issue of improper access control through proper process isolation and terminal session management. Organizations should also implement monitoring to detect any unauthorized terminal access attempts and establish regular security assessments to identify similar access control vulnerabilities in other system components. The fix ensures that daemon processes operate in isolated environments without access to controlling terminal sessions, thereby preventing the exploitation vectors that could lead to privilege escalation or unauthorized system access.