CVE-2016-3936 in Android
Summary
by MITRE
The MediaTek video driver in Android before 2016-10-05 allows attackers to gain privileges via a crafted application, aka Android internal bug 30019037 and MediaTek internal bug ALPS02829568.
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Analysis
by VulDB Data Team • 05/01/2019
The vulnerability identified as CVE-2016-3936 represents a critical privilege escalation flaw within the MediaTek video driver component of Android operating systems. This issue affects Android versions prior to the security patch released on October 5, 2016, and is catalogued under Android internal bug 30019037 with MediaTek's internal tracking number ALPS02829568. The flaw exists in the kernel-level video driver implementation that processes multimedia content, creating an avenue for malicious applications to elevate their privileges beyond normal user restrictions. The vulnerability stems from improper input validation and memory handling within the driver's processing routines, allowing crafted applications to exploit memory corruption vulnerabilities that ultimately lead to privilege escalation.
The technical exploitation of this vulnerability occurs through the manipulation of video processing commands that flow through the MediaTek video driver interface. Attackers can craft malicious applications that send specially formatted video data or control sequences to the vulnerable driver component, triggering memory corruption conditions that enable privilege escalation. This flaw operates at the kernel level where the video driver executes with elevated privileges, making it particularly dangerous as it allows attackers to bypass normal Android security boundaries. The vulnerability is classified as a privilege escalation vulnerability under CWE-264, specifically related to permissions, privileges, and access controls within operating systems. The exploitation process typically involves sending malformed video frames or control parameters that cause buffer overflows or use-after-free conditions within the driver's memory management.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with complete system control capabilities. Once successfully exploited, malicious applications can access all system resources, modify critical system files, install unauthorized applications, and potentially exfiltrate sensitive user data. The vulnerability affects devices running Android versions prior to the October 2016 security patch, making a substantial portion of the Android ecosystem susceptible to this attack vector. Security researchers have documented that this flaw can be leveraged to bypass Android's security model, including the application sandboxing mechanisms and SELinux policies that normally protect system integrity. The impact is particularly severe because the vulnerability operates at the driver level, making it difficult to detect through standard application-level security measures and requiring system-level patching to resolve.
Mitigation strategies for CVE-2016-3936 focus primarily on applying the relevant Android security patches released in October 2016. Device manufacturers and carriers should immediately deploy the security updates that contain fixes for the MediaTek video driver vulnerability. Organizations should also implement application whitelisting policies to prevent installation of untrusted applications that could exploit this vulnerability, though this approach provides only partial protection as the flaw exists in system-level components. Network-level monitoring should be enhanced to detect unusual video processing activities that might indicate exploitation attempts, though such detection is challenging due to the legitimate use of video processing functionality. The vulnerability demonstrates the importance of secure driver development practices and proper input validation, aligning with ATT&CK technique T1068 which covers the use of privilege escalation techniques. Device users should be advised to update their systems promptly and avoid installing applications from untrusted sources, as the vulnerability requires a malicious application to be installed on the device for exploitation to occur.