CVE-2019-5013 in Driver
Summary
by MITRE
An exploitable privilege escalation vulnerability exists in the Wacom, driver version 6.3.32-3, update helper service in the start/stopLaunchDProcess command. The command takes a user-supplied string argument and executes launchctl under root context. A user with local access can use this vulnerability to raise load arbitrary launchD agents. An attacker would need local access to the machine for a successful exploit.
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Analysis
by VulDB Data Team • 01/27/2024
The vulnerability identified as CVE-2019-5013 represents a critical privilege escalation flaw within the Wacom driver update helper service, specifically affecting version 6.3.32-3 of the software. This issue resides in the start/stopLaunchDProcess command implementation where the service executes launchctl commands with elevated privileges under the root context. The flaw stems from inadequate input validation and sanitization within the helper service, creating a path where untrusted user input directly influences system command execution. This design vulnerability allows for arbitrary code injection through the launchctl utility, which is typically used for managing launchd agents and daemons on macOS systems. The security implications are particularly severe because launchd processes operate with system-level privileges, making this a prime target for attackers seeking to escalate their privileges and gain unauthorized control over the affected system.
The technical exploitation of this vulnerability requires local system access, which aligns with the attack pattern described in the ATT&CK framework under privilege escalation techniques. The flaw manifests when a malicious user supplies a crafted string argument to the start/stopLaunchDProcess command, which then gets passed directly to launchctl without proper sanitization or validation. This creates a command injection scenario where the helper service executes the user-supplied string as a system command with root privileges. The vulnerability is categorized as a CWE-78 (Improper Neutralization of Special Elements used in OS Command) and falls under the broader category of CWE-20 (Improper Input Validation) due to the lack of proper validation of user-supplied input. The launchctl utility, when executed with root privileges, can load arbitrary launchd agents and daemons, effectively allowing the attacker to install persistent backdoors or malicious services that will execute with system-level privileges. This capability fundamentally undermines the security model of macOS, as it enables attackers to establish persistent access to the system without requiring additional authentication or authorization mechanisms.
The operational impact of CVE-2019-5013 extends beyond simple privilege escalation, as it provides attackers with a mechanism to establish persistent access and potentially execute arbitrary code with full system privileges. Once exploited, the attacker can install malicious launchd agents that will automatically execute upon system boot or user login, creating a stealthy persistence mechanism that is difficult to detect and remove. The vulnerability affects all systems running the affected Wacom driver version and is particularly concerning because the helper service runs with elevated privileges, making it an attractive target for attackers seeking to establish a foothold within the system. This type of vulnerability is commonly exploited in advanced persistent threat campaigns where attackers seek to maintain long-term access to compromised systems. The attack surface is limited to local access requirements, but this makes the vulnerability particularly dangerous in environments where physical access or local account compromise is possible, such as shared workstations or systems with weak local security controls. Security professionals should note that the vulnerability can be exploited without requiring network access or remote code execution capabilities, making it a particularly insidious threat vector.
Mitigation strategies for CVE-2019-5013 should focus on both immediate remediation and long-term security hardening measures. The most effective immediate solution involves updating to a patched version of the Wacom driver where the input validation has been properly implemented to prevent command injection attacks. System administrators should also consider implementing additional security controls such as restricting local access to systems, implementing proper privilege separation, and monitoring for unusual launchctl activity. The principle of least privilege should be enforced by ensuring that helper services run with minimal required privileges rather than elevated root access. Organizations should also consider implementing application whitelisting policies to prevent unauthorized execution of launchd agents and monitor system logs for suspicious launchctl commands. The vulnerability highlights the importance of secure coding practices and input validation in privileged system components, as outlined in various security standards including the OWASP Top 10 and NIST cybersecurity frameworks. Regular security assessments and vulnerability scanning should include checks for similar privilege escalation vulnerabilities in system services and helper applications to prevent similar issues from being exploited in the future.