CVE-2016-10810 in cPanel
Summary
by MITRE
In cPanel before 57.9999.54, /scripts/maildir_converter exposed a TTY to an unprivileged process (SEC-115).
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 07/22/2020
The vulnerability identified as CVE-2016-10810 affects cPanel versions prior to 57.9999.54 and stems from improper handling of terminal I/O during the maildir conversion process. This flaw allows unprivileged processes to gain access to a TTY device that should remain restricted to privileged operations. The issue was categorized as SEC-115 within cPanel's security advisory framework, highlighting its potential to undermine system security controls.
The technical root cause of this vulnerability lies in the /scripts/maildir_converter utility which fails to properly manage terminal session access during its execution. When this script runs, it inadvertently exposes a TTY device to processes that do not possess the necessary privileges to access such system resources. This exposure creates an attack surface where malicious users could potentially exploit the TTY access to escalate privileges or gain unauthorized system access. The vulnerability essentially represents a privilege escalation vector that bypasses normal access control mechanisms.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it enables attackers to manipulate terminal sessions and potentially execute arbitrary commands with elevated privileges. An unprivileged user who can trigger the maildir conversion process gains access to a TTY that should normally be restricted to system administrators or privileged processes. This access could facilitate various malicious activities including but not limited to command injection, session hijacking, or further system compromise. The vulnerability particularly affects shared hosting environments where multiple users operate on the same system, increasing the attack surface and potential impact.
This vulnerability aligns with CWE-276, which addresses improper privilege management, and demonstrates how inadequate access control mechanisms can lead to unauthorized system access. From an ATT&CK framework perspective, this issue maps to privilege escalation techniques where adversaries exploit weak access controls to gain elevated system privileges. The vulnerability also reflects poor input validation and improper resource management practices that are commonly exploited in system-level attacks. Organizations should implement immediate mitigations including updating to cPanel version 57.9999.54 or later, which contains the necessary patches to properly restrict TTY access during maildir conversion operations.
The remediation strategy involves not only applying the vendor-provided security update but also implementing monitoring for unauthorized TTY access attempts and reviewing system access controls for similar privilege escalation vectors. System administrators should conduct comprehensive security audits to identify other scripts or processes that might expose terminal sessions to unprivileged users. Regular security assessments should include validation of access control mechanisms and privilege boundaries to prevent similar vulnerabilities from emerging in other system components. The incident underscores the importance of proper TTY handling and terminal session management in maintaining system integrity and preventing unauthorized privilege escalation attacks.