CVE-2017-15850 in Android
Summary
by MITRE
In Android for MSM, Firefox OS for MSM, QRD Android, with all Android releases from CAF using the Linux kernel, userspace can read values from audio codec registers.
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Analysis
by VulDB Data Team • 12/22/2019
This vulnerability exists within the Linux kernel implementation of audio codec drivers across multiple Android platforms including MSM, Firefox OS, and QRD Android variants. The flaw allows unprivileged userspace processes to directly access and read sensitive register values from audio codec hardware components. The vulnerability stems from inadequate kernel-level access controls and register protection mechanisms within the audio subsystem drivers. Attackers can exploit this weakness to extract confidential information about the audio hardware configuration, potentially revealing proprietary codec parameters, firmware versions, or hardware-specific identifiers that could aid in further exploitation attempts.
The technical implementation of this vulnerability involves improper kernel driver design where audio codec register mappings lack proper access validation checks. When userspace applications attempt to read from audio codec registers through kernel interfaces, the system fails to enforce appropriate privilege checks or memory protection boundaries. This creates a direct information disclosure channel that bypasses normal kernel security mechanisms. The vulnerability affects all Android releases from CAF that utilize the Linux kernel, indicating a widespread impact across multiple device manufacturers and hardware platforms. The flaw specifically targets the audio subsystem's register access interfaces, which are typically protected but improperly exposed to unprivileged processes.
Operationally, this vulnerability presents significant security implications for mobile device security. An attacker with local access to a compromised device can extract detailed information about the underlying audio hardware configuration, potentially enabling more sophisticated attacks. The leaked register values could reveal hardware-specific details that aid in crafting targeted exploits against other components of the audio subsystem or the broader device firmware. This information disclosure could also facilitate bypassing hardware-based security features or contribute to understanding the device's hardware architecture for advanced exploitation techniques. The vulnerability particularly affects devices where audio codec information could be leveraged to understand the device's security posture or to develop more effective attack vectors against other system components.
Mitigation strategies should focus on implementing proper kernel-level access controls for audio codec register interfaces. System administrators and device manufacturers should ensure that audio codec register access is properly restricted through kernel security modules and proper privilege validation mechanisms. The recommended approach involves updating kernel implementations to enforce strict access controls on audio hardware registers, ensuring that only authorized kernel components can access these sensitive registers. Additionally, implementing proper kernel memory protection mechanisms and access control lists can prevent unauthorized userspace access to hardware registers. Regular security updates and kernel patches should be applied to address this vulnerability across affected platforms. The mitigation efforts align with common security practices outlined in the CWE catalog under information disclosure vulnerabilities and should be coordinated with standard security frameworks such as those referenced in the ATT&CK matrix for mobile device security operations.