CVE-2019-9730 in Sound Device Driver
Summary
by MITRE
Incorrect access control in the CxUtilSvc component of the Synaptics Sound Device drivers prior to version 2.29 allows a local attacker to increase access privileges to the Windows Registry via an unpublished API.
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Analysis
by VulDB Data Team • 06/20/2020
The vulnerability identified as CVE-2019-9730 represents a critical access control flaw within the Synaptics Sound Device drivers, specifically affecting the CxUtilSvc component. This issue manifests in versions prior to 2.29 and creates a significant security risk by allowing local attackers to escalate their privileges through an unpublished Application Programming Interface. The flaw resides within the driver's privilege management mechanisms, where improper access controls fail to properly validate the privileges of processes attempting to interact with the Windows Registry through this specific service interface.
The technical implementation of this vulnerability stems from the lack of proper authentication and authorization checks within the CxUtilSvc service. When a local attacker successfully invokes the unpublished API, the service fails to verify whether the calling process possesses sufficient privileges to modify registry entries. This oversight creates a privilege escalation pathway that bypasses normal Windows security mechanisms and allows unauthorized modifications to critical system registry keys. The vulnerability operates at the kernel level within the driver component, making it particularly dangerous as it can be exploited without requiring elevated permissions initially.
From an operational perspective, this vulnerability presents a substantial risk to system integrity and security posture. Local attackers can leverage this flaw to modify registry entries that control audio device behavior, potentially enabling persistent backdoor access or system instability. The impact extends beyond simple privilege escalation as registry modifications can affect driver loading sequences, system boot processes, and overall audio functionality. Attackers could use this capability to establish persistence mechanisms, modify device behavior to hide malicious activities, or create conditions that facilitate further exploitation. The unpublished nature of the API makes detection more challenging as security tools may not be aware of this specific interface.
This vulnerability aligns with CWE-284, which describes improper access control, and demonstrates characteristics consistent with the ATT&CK technique T1068 for local privilege escalation. The flaw represents a classic example of insufficient privilege checking within a system service, creating an attack surface that can be exploited to gain elevated system privileges. Organizations should prioritize patching this vulnerability as it provides a direct pathway for attackers to escalate privileges and potentially gain full system control. The remediation requires updating to Synaptics driver version 2.29 or later, which implements proper access control checks for the CxUtilSvc component. Additionally, system administrators should monitor for unusual registry modifications and consider implementing additional security controls such as registry protection mechanisms and enhanced monitoring of driver service interactions to detect potential exploitation attempts.