CVE-2016-5861 in Android
Summary
by MITRE
In a display driver in all Qualcomm products with Android releases from CAF using the Linux kernel, a variable controlled by userspace is used to calculate offsets and sizes for copy operations, which could result in heap overflow.
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Analysis
by VulDB Data Team • 12/15/2022
The vulnerability identified as CVE-2016-5861 resides within the display driver component of Qualcomm products running Android operating systems based on the Linux kernel. This flaw represents a critical security issue that stems from improper input validation and memory management practices within the kernel-level driver responsible for handling graphics operations. The vulnerability affects all Qualcomm products that utilize Android releases from the Code Aurora Forum (CAF) and operates at the intersection of kernel space and user space interactions, creating a dangerous attack surface that can be exploited by malicious actors.
The technical flaw manifests when a variable originating from userspace is utilized to compute offsets and sizes for memory copy operations within the kernel driver. This design decision creates a direct pathway for arbitrary data manipulation that can lead to heap overflow conditions. The variable in question is not properly validated or sanitized before being used in calculations that determine memory allocation boundaries and copy parameters. This allows a malicious user process to manipulate the input values in such a way that the driver performs memory operations beyond the intended boundaries, potentially overwriting adjacent heap memory regions. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, though it manifests in heap memory due to the nature of the copy operations involved.
The operational impact of this vulnerability extends beyond simple memory corruption, as it provides potential attackers with opportunities for privilege escalation and system compromise. When heap overflow occurs in kernel space, the attacker can manipulate critical data structures, overwrite function pointers, or corrupt kernel memory in ways that may allow execution of arbitrary code with kernel-level privileges. This creates a severe threat vector that can be leveraged for persistent system compromise, data exfiltration, or complete system takeover. The vulnerability is particularly dangerous because it operates within the graphics driver stack, which typically runs with elevated privileges and has direct access to hardware resources that can be exploited for further attacks.
Mitigation strategies for CVE-2016-5861 must address the fundamental flaw in input validation and memory management practices within the affected display drivers. The primary remediation involves implementing proper bounds checking and input validation for all user-supplied variables used in memory calculation operations. This includes sanitizing all inputs before they are used to determine memory offsets and sizes, implementing proper bounds checking for copy operations, and ensuring that memory allocations are properly validated against expected ranges. Organizations should also implement kernel memory protection mechanisms such as stack canaries, address space layout randomization, and kernel address space protection features that can detect and prevent exploitation attempts. The vulnerability aligns with several ATT&CK techniques including privilege escalation through kernel exploits and defense evasion by manipulating system memory structures. Regular security updates and patches from Qualcomm and Android vendors are essential to address this vulnerability, as it requires kernel-level modifications that cannot be resolved through user-space applications alone.