CVE-2016-3756 in Android
Summary
by MITRE
Tremolo/res012.c in mediaserver in Android 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, and 6.x before 2016-07-01 does not validate the number of partitions, which allows remote attackers to cause a denial of service (device hang or reboot) via a crafted media file, aka internal bug 28556125.
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Analysis
by VulDB Data Team • 02/22/2019
The vulnerability identified as CVE-2016-3756 resides within the mediaserver component of Android operating systems, specifically affecting versions prior to their respective security patches released in 2016. This flaw is located in the Tremolo/res012.c file which processes media files within the Android media framework. The vulnerability represents a classic case of insufficient input validation where the system fails to properly validate the number of partitions in crafted media files, creating a path for malicious actors to exploit device stability through carefully constructed audio or video content.
The technical nature of this vulnerability stems from a lack of proper bounds checking within the media parsing logic. When the mediaserver processes a media file, it expects a specific number of partitions or segments within the file structure. However, the code does not validate whether the actual number of partitions matches expected parameters or falls within acceptable ranges. This absence of validation creates a condition where an attacker can craft a media file containing an excessive or malformed number of partitions that causes the mediaserver to enter an infinite loop or consume excessive system resources. The vulnerability operates at the kernel level within the Android media subsystem, making it particularly dangerous as it can trigger system-level failures that result in complete device instability.
The operational impact of this vulnerability manifests as a denial of service condition that can either cause the device to hang or force a complete reboot. This occurs because the malformed media file triggers an unhandled exception within the mediaserver process, leading to a cascade of system failures that ultimately results in device unresponsiveness. Attackers can exploit this vulnerability remotely by delivering malicious media files through various channels including email attachments, web downloads, or malicious applications that play such media content automatically. The vulnerability is particularly concerning because it affects multiple Android versions simultaneously, including the widely deployed Android 4.x through 6.x releases, potentially impacting millions of devices across different manufacturers and hardware configurations.
This vulnerability maps directly to CWE-129, which describes improper validation of array indices or other bounds checking issues, and aligns with ATT&CK technique T1499.001 for Network Denial of Service. The attack surface is broad as it can be triggered through any media playback functionality, including standard media players, messaging applications, web browsers, and third-party media applications. The exploit requires minimal privileges and can be executed through automated means, making it particularly dangerous for widespread deployment. Organizations should note that this vulnerability represents a critical security gap in mobile device management, as it can be exploited without user interaction in certain scenarios where media files are automatically played.
Mitigation strategies for this vulnerability should include immediate deployment of the security patches released by Google for the affected Android versions, specifically targeting the mediaserver component and the partition validation logic. System administrators should implement media content filtering policies to prevent the automatic playback of untrusted media files, particularly in enterprise environments where device security is paramount. Additionally, regular security assessments should verify that all media processing components within Android systems properly validate input parameters and implement robust bounds checking mechanisms. The vulnerability highlights the importance of input validation in mobile operating systems and underscores the need for comprehensive security testing of media processing frameworks to prevent similar issues from emerging in future releases.