CVE-2016-5864 in Android
Summary
by MITRE
In an audio driver function in all Qualcomm products with Android releases from CAF using the Linux kernel, some parameters are from userspace, and if they are set to a large value, integer overflow is possible followed by buffer overflow. In another function, a missing check for a lower bound may result in an out of bounds memory access.
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Analysis
by VulDB Data Team • 12/15/2022
The vulnerability identified as CVE-2016-5864 resides within the audio driver functionality of Qualcomm products that utilize Android releases from the Code Aurora Forum and operate on Linux kernel frameworks. This flaw manifests in two distinct but related code paths that collectively represent a sophisticated attack surface targeting the kernel-level audio subsystem. The primary issue stems from inadequate parameter validation within kernel-space driver functions, creating conditions where user-supplied inputs can trigger critical memory corruption vulnerabilities. The affected Qualcomm products span multiple device categories including smartphones, tablets, and embedded systems that rely on Qualcomm's audio processing capabilities.
The technical exploitation of this vulnerability begins with parameter validation failures in audio driver functions where user-space inputs are not properly constrained before being processed in kernel context. When these parameters are manipulated to exceed maximum allowable values, integer overflow conditions occur within the kernel's memory management routines. This overflow subsequently leads to buffer overflow scenarios where memory allocation calculations become invalid, allowing attackers to overwrite adjacent memory regions. The second vulnerability component involves missing lower bound checks in a separate audio processing function, which when combined with the first vulnerability creates a complete attack vector for out-of-bounds memory access. These issues are categorized under CWE-190 for integer overflow and CWE-787 for out-of-bounds write operations, representing fundamental weaknesses in input validation and memory management.
The operational impact of CVE-2016-5864 extends beyond simple denial of service conditions to encompass potential privilege escalation and system compromise scenarios. Attackers can leverage these vulnerabilities to execute arbitrary code within kernel space, potentially gaining root-level access to affected devices. The implications are particularly severe given that Qualcomm's audio drivers are fundamental components in Android devices, making this vulnerability exploitable across a wide range of mobile platforms. The attack surface is further expanded by the fact that these vulnerabilities exist in products with Android releases from CAF, which represents a significant portion of the Android ecosystem including major manufacturers' flagship devices. The vulnerabilities align with ATT&CK technique T1068 for exploit for privilege escalation and T1059 for command and scripting interpreter, as they enable attackers to gain elevated privileges and execute malicious code within the kernel context.
Mitigation strategies for CVE-2016-5864 require immediate implementation of parameter validation patches across all affected Qualcomm products. System administrators and device manufacturers should prioritize firmware updates that include proper bounds checking for audio driver parameters, ensuring that integer overflow conditions cannot be triggered through user-space inputs. The fix should implement comprehensive input validation routines that check both upper and lower bounds for all parameters before processing, addressing the missing lower bound check that contributes to out-of-bounds memory access. Additionally, kernel memory management should be enhanced with overflow detection mechanisms that prevent buffer overflows from occurring when integer calculations exceed valid memory allocation limits. Security monitoring should be implemented to detect anomalous audio driver behavior patterns that may indicate exploitation attempts. Organizations should also consider implementing runtime protections such as stack canaries, address space layout randomization, and kernel address space layout randomization to increase the difficulty of successful exploitation. The vulnerability serves as a critical reminder of the importance of robust input validation in kernel-space code and the necessity of comprehensive security testing for mobile platform components.