CVE-2023-20942 in Android
Summary
by MITRE • 07/13/2023
In openMmapStream of AudioFlinger.cpp, there is a possible way to record audio without displaying the microphone privacy indicator due to a logic error in the code. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.
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Analysis
by VulDB Data Team • 08/05/2023
The vulnerability identified as CVE-2023-20942 resides within the openMMapStream function of AudioFlinger.cpp in the Android operating system, representing a critical security flaw that undermines the device's audio privacy protections. This issue stems from a logic error that allows malicious applications to capture audio input without triggering the expected microphone privacy indicator, effectively bypassing fundamental user consent mechanisms that are designed to prevent unauthorized audio recording.
The technical implementation of this vulnerability involves a flaw in the permission checking logic within the audio streaming subsystem where the system fails to properly validate whether an application has legitimate authorization to access microphone input. This logic error occurs during the initialization of memory-mapped audio streams, where the code path that should enforce privacy indicators becomes bypassed due to improper conditional statements or missing validation checks. The flaw specifically affects the AudioFlinger component which manages audio hardware resources and stream processing, making it a core system service that handles audio input/output operations across the device.
From an operational perspective, this vulnerability enables local privilege escalation without requiring any additional execution privileges or user interaction, making it particularly dangerous as it can be exploited by malicious applications already present on the device. The absence of user notification through the microphone privacy indicator creates a stealthy attack vector where users remain unaware of unauthorized audio capture activities. This vulnerability directly impacts the Android security model's principle of least privilege and user consent, as it allows applications to circumvent the expected privacy controls that should be enforced by the operating system's security framework.
The implications of this vulnerability extend beyond simple privacy concerns to potentially enable more sophisticated attacks where adversaries can collect sensitive audio data without user knowledge. This flaw represents a failure in the Android security architecture's input validation and access control mechanisms, specifically related to the system's ability to enforce privacy indicators for audio recording operations. The vulnerability aligns with CWE-691, which addresses insufficient control flow management, and could be categorized under ATT&CK technique T1123 for "Audio Capture" where adversaries gain access to microphone input without proper user awareness.
Mitigation strategies for this vulnerability require immediate system updates from device manufacturers and Google to patch the logic error in AudioFlinger.cpp. Organizations should ensure their Android devices receive timely security patches and implement monitoring solutions that can detect unauthorized audio access patterns. Users should maintain updated device software and exercise caution when installing applications that request microphone permissions, particularly those that operate in the background without clear user consent. Additionally, system administrators should consider implementing mobile device management policies that restrict audio recording capabilities and monitor for suspicious audio access patterns that could indicate exploitation of this vulnerability. The fix must address the specific conditional logic error that bypasses the microphone privacy indicator and ensure proper validation of audio access requests throughout the audio streaming pipeline.