CVE-2016-6791 in Android
Summary
by MITRE
An elevation of privilege vulnerability in the Qualcomm sound driver could enable a local malicious application to execute arbitrary code within the context of the kernel. This issue is rated as High because it first requires compromising a privileged process. Product: Android. Versions: Kernel-3.10, Kernel-3.18. Android ID: A-31252384. References: QC-CR#1071809.
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Analysis
by VulDB Data Team • 07/20/2020
The vulnerability identified as CVE-2016-6791 represents a critical elevation of privilege flaw within the Qualcomm sound driver component of Android operating systems. This weakness exists in kernel versions 3.10 and 3.18, making it particularly concerning given the widespread adoption of these kernel versions across various Android devices. The vulnerability operates through a privilege escalation mechanism that allows a local malicious application to execute arbitrary code with kernel-level privileges, effectively bypassing the normal security boundaries that protect the operating system's core functions. The issue is classified as High severity due to its requirement for an initial compromise of a privileged process, which creates a significant attack vector for determined adversaries.
The technical flaw stems from improper input validation and memory management within the Qualcomm sound driver implementation. When processing audio-related system calls or data structures, the driver fails to adequately validate user-supplied parameters, creating opportunities for attackers to manipulate kernel memory layouts or execute malicious code sequences. This vulnerability specifically affects the kernel's handling of audio device interactions and could be exploited through carefully crafted audio processing operations that leverage buffer overflows, use-after-free conditions, or other memory corruption patterns. The flaw operates at the kernel level, meaning that successful exploitation would provide attackers with complete control over the device's audio subsystem and potentially broader system access.
The operational impact of this vulnerability extends beyond simple audio functionality compromise, as it provides attackers with kernel-level execution capabilities that can be leveraged for more sophisticated attacks. Once a malicious application gains kernel privileges through this vulnerability, it can manipulate system memory, modify security policies, access sensitive data, and potentially establish persistent backdoors. The attack requires initial compromise of a privileged process, which aligns with the attack pattern described in the attack technique matrix under technique T1068 for exploiting privileges. This requirement makes the vulnerability somewhat more difficult to exploit directly but still represents a significant threat vector for attackers who can first compromise a legitimate privileged application or service.
Mitigation strategies for CVE-2016-6791 should focus on both immediate patching and defensive measures. Device manufacturers should prioritize updating affected kernel versions to patched releases that address the specific memory handling and input validation issues within the Qualcomm sound driver. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-122, which covers heap-based buffer overflow scenarios. Security teams should also implement runtime monitoring to detect suspicious kernel-level activities and consider applying kernel hardening techniques such as stack canaries, address space layout randomization, and kernel module signing. Additionally, the Android security model should enforce stricter application sandboxing and privilege separation to limit the potential impact of compromised privileged processes. Organizations should also review their incident response procedures to ensure rapid detection and remediation of potential exploitation attempts.