CVE-2017-7293 in Audio X2
Summary
by MITRE
The Dolby DAX2 and DAX3 API services are vulnerable to a privilege escalation vulnerability that allows a normal user to get arbitrary system privileges, because these services have .NET code for DCOM. This affects Dolby Audio X2 (DAX2) 1.0, 1.0.1, 1.1, 1.1.1, 1.2, 1.3, 1.3.1, 1.3.2, 1.4, 1.4.1, 1.4.2, 1.4.3, and 1.4.4 and Dolby Audio X3 (DAX3) 1.0 and 1.1. An example affected driver is Realtek Audio Driver 6.0.1.7898 on a Lenovo P50.
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Analysis
by VulDB Data Team • 09/21/2020
The vulnerability identified as CVE-2017-7293 represents a critical privilege escalation flaw within Dolby DAX2 and DAX3 audio processing services that directly impacts system security integrity. These services operate as Windows components that provide advanced audio enhancement capabilities through the Dolby Audio platform, specifically targeting consumer and enterprise devices that utilize Dolby's audio processing technologies. The affected versions include multiple iterations of both DAX2 and DAX3 services, with the vulnerability manifesting in the form of improperly secured DCOM (Distributed Component Object Model) interfaces that expose the underlying .NET code execution environment.
The technical root cause of this vulnerability stems from the insecure implementation of DCOM interfaces within the Dolby audio services, which allows unprivileged users to leverage these interfaces to execute arbitrary code with elevated privileges. This flaw specifically exploits the trust model inherent in DCOM services where the system grants elevated permissions to processes that are improperly configured to handle unauthenticated or insufficiently authenticated requests. The vulnerability manifests when normal user processes attempt to interact with the DCOM endpoints exposed by the Dolby services, which then execute .NET code with system-level privileges due to inadequate access control mechanisms and privilege separation. This represents a classic example of a privilege escalation vulnerability where the system's security boundaries are bypassed through improper service configuration.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and unauthorized access to sensitive system resources. Attackers can leverage this vulnerability to gain system-level control over affected devices, potentially leading to complete system takeover, data exfiltration, or deployment of additional malicious payloads. The vulnerability affects a wide range of consumer and enterprise devices, particularly those utilizing Realtek audio drivers on Lenovo systems, indicating the widespread nature of the exposure. The attack surface is particularly concerning given that these audio services typically run with elevated privileges and are accessible to standard user accounts, creating an ideal environment for privilege escalation attacks.
The vulnerability aligns with CWE-269, which addresses "Improper Privilege Management" and specifically relates to inadequate access control mechanisms that allow unauthorized users to gain elevated privileges. From an ATT&CK framework perspective, this vulnerability maps to T1068, which covers "Exploitation for Privilege Escalation," and T1059, covering "Command and Scripting Interpreter," as the exploitation involves the execution of code through .NET interfaces. The attack chain typically begins with a user-level process interacting with the vulnerable DCOM service, followed by privilege escalation through the execution of .NET code with elevated system privileges. The remediation approach must address the fundamental service configuration issues, including proper access control implementation, privilege separation, and secure DCOM interface management.
Organizations should implement immediate mitigations including disabling or removing the vulnerable Dolby services from affected systems, applying vendor patches once available, and implementing network segmentation to limit access to these services. System administrators should conduct comprehensive vulnerability assessments to identify all affected systems and ensure that audio services are properly configured with minimal required privileges. The vulnerability also highlights the importance of secure coding practices in Windows services, particularly around DCOM interface implementation and privilege management. Given the widespread nature of the affected software, organizations should prioritize patch management processes and consider implementing additional monitoring to detect unauthorized access attempts to audio services. The incident underscores the need for comprehensive security testing of audio and multimedia services, as these components often operate with elevated privileges and can serve as attack vectors for privilege escalation.