CVE-2016-8459 in Android
Summary
by MITRE
Possible buffer overflow in storage subsystem. Bad parameters as part of listener responses to RPMB commands could lead to buffer overflow. Product: Android. Versions: Kernel 3.18. Android ID: A-32577972. References: QC-CR#988462.
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Analysis
by VulDB Data Team • 01/04/2017
The vulnerability identified as CVE-2016-8459 represents a critical buffer overflow condition within the Android kernel's storage subsystem, specifically affecting the RPMB (Replay Protection Memory Block) command processing mechanism. This issue originates from improper parameter validation within the kernel's response handling logic for RPMB commands, creating a potential exploitation vector that could allow malicious actors to manipulate memory structures and potentially execute arbitrary code. The vulnerability affects Android devices running kernel version 3.18, making it particularly concerning given the widespread deployment of this kernel version across various mobile platforms and embedded systems. The Android ID A-32577972 indicates this was properly tracked within Google's internal vulnerability management system, highlighting the severity of the issue and its potential impact on device security.
The technical flaw manifests when the kernel processes listener responses to RPMB commands, where insufficient input validation allows for malformed parameters to be passed into buffer allocation routines. This specific implementation error creates a classic buffer overflow scenario where attacker-controlled data can exceed the bounds of allocated memory regions, potentially overwriting adjacent memory locations including function return addresses, stack canaries, or other critical kernel data structures. The vulnerability operates at the kernel level, meaning successful exploitation could result in complete system compromise, privilege escalation, and potential persistence mechanisms within the device's storage subsystem. The RPMB functionality itself is designed to provide secure storage for critical device data, making this vulnerability particularly dangerous as it targets the very mechanisms intended to protect device integrity.
The operational impact of CVE-2016-8459 extends beyond simple memory corruption, as it represents a significant threat to Android device security and could enable sophisticated attack scenarios. Attackers could potentially exploit this vulnerability to gain root-level access to affected devices, allowing them to modify system files, extract sensitive data, or install persistent malware. The vulnerability's location within the storage subsystem means it could be triggered through various attack vectors including malicious SD card content, compromised firmware updates, or specially crafted storage operations that would normally be benign. This type of vulnerability falls under CWE-121, which specifically addresses stack-based buffer overflow conditions, and aligns with ATT&CK technique T1059.001 for command and scripting interpreter usage, as exploitation would likely involve manipulating system commands through compromised storage interfaces.
Mitigation strategies for this vulnerability require immediate kernel updates and patches from device manufacturers, as the issue resides within the core operating system components that cannot be easily patched through standard application updates. Organizations and users should prioritize updating to patched kernel versions, typically those containing the fixes for Android security bulletin releases from late 2016. Device manufacturers should implement robust input validation routines for all RPMB command processing, including parameter length checks and bounds verification before any memory allocation occurs. Additionally, implementing memory protection mechanisms such as stack canaries, address space layout randomization, and kernel address space layout randomization could help mitigate exploitation attempts. The vulnerability also highlights the importance of secure coding practices and thorough security testing for kernel-level components, particularly those handling sensitive device storage functions. Given the nature of the vulnerability and its potential for privilege escalation, comprehensive security audits of storage subsystems should be conducted to identify similar buffer overflow conditions that may exist in other kernel modules or device drivers.