CVE-2016-6761 in Android
Summary
by MITRE
An elevation of privilege vulnerability in Qualcomm media codecs could enable a local malicious application to execute arbitrary code within the context of a privileged process. This issue is rated as High because it could be used to gain local access to elevated capabilities, which are not normally accessible to a third-party application. Product: Android. Versions: Kernel-3.10, Kernel-3.18. Android ID: A-29421682. References: QC-CR#1055792.
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Analysis
by VulDB Data Team • 07/20/2020
This vulnerability resides within the Qualcomm media codecs implementation on Android devices, representing a critical elevation of privilege flaw that allows local malicious applications to execute arbitrary code with heightened privileges. The issue stems from improper input validation and memory handling within the media codec processing pipeline, specifically affecting kernel versions 3.10 and 3.18. The vulnerability is classified as high severity because it provides attackers with the capability to bypass normal security boundaries and access privileged system functions that should remain restricted to trusted system components. According to the Android security advisory A-29421682, this flaw enables a local attacker to escalate their privileges from a standard application context to that of a privileged system process, fundamentally compromising the device's security model.
The technical exploitation of this vulnerability occurs through the manipulation of media codec parameters during audio or video processing operations. When a malicious application attempts to process specially crafted media files, the Qualcomm media codec implementation fails to properly validate input data, leading to memory corruption that can be leveraged to execute arbitrary code within the privileged context of the media processing daemon. This flaw typically manifests as a buffer overflow or use-after-free condition within the kernel-level media processing components, allowing the attacker to overwrite critical memory structures or inject malicious code that executes with the privileges of the system-level media service. The vulnerability affects the Android framework's media subsystem and specifically targets the Qualcomm proprietary codec implementations that handle multimedia processing at the kernel level.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally undermines the Android security architecture's principle of least privilege. Once exploited, the malicious application can access system resources, modify critical system files, disable security features, and potentially establish persistent backdoors on the device. This capability enables attackers to perform actions such as reading sensitive user data, modifying system configurations, installing additional malicious software, or even disabling security mechanisms like SELinux policies. The vulnerability is particularly concerning because it requires no user interaction beyond installing a malicious application, making it a latent threat that can be exploited silently in the background. From a threat modeling perspective, this vulnerability aligns with attack patterns described in the ATT&CK framework under privilege escalation techniques, specifically targeting kernel-level exploitation methods.
Mitigation strategies for this vulnerability include immediate patching of the affected kernel versions through Android security updates, which typically involve fixing the input validation routines and memory handling within the Qualcomm media codec implementations. System administrators should ensure that devices are updated with the latest security patches from Google and device manufacturers, particularly focusing on kernel updates that address the specific memory corruption issues in the media processing components. Additional protective measures include implementing application sandboxing policies that restrict media processing capabilities, monitoring for suspicious media file processing activities, and enabling security features like kernel address space layout randomization. The vulnerability also highlights the importance of proper code review processes for vendor-specific kernel modules, aligning with CWE guidelines that emphasize the need for proper input validation and memory management in kernel-level code. Organizations should also consider implementing network-based monitoring solutions to detect potential exploitation attempts and maintain comprehensive incident response procedures for handling privilege escalation attacks.