CVE-2016-3899 in Android
Summary
by MITRE
OMXCodec.cpp in libstagefright in mediaserver in Android 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, 6.x before 2016-09-01, and 7.0 before 2016-09-01 does not validate a certain pointer, which allows remote attackers to cause a denial of service (device hang or reboot) via a crafted media file, aka internal bug 29421811.
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Analysis
by VulDB Data Team • 09/15/2022
The vulnerability described in CVE-2016-3899 represents a critical security flaw within the Android media processing framework that affects multiple versions of the operating system. This issue resides in the OMXCodec.cpp component of libstagefright, which serves as the core media decoding library for the Android media server process. The vulnerability stems from insufficient pointer validation during media file processing, creating a condition where maliciously crafted media content can trigger unexpected behavior in the system's media handling mechanisms. The affected versions span across Android 4.x through 7.0, with specific patches released to address the issue in each affected release line. This flaw specifically impacts the mediaserver process which handles all media decoding operations for the Android system, making it a prime target for exploitation.
The technical nature of this vulnerability involves a missing pointer validation check within the media decoding pipeline that processes multimedia files. When the mediaserver encounters a specially crafted media file, the OMXCodec component fails to properly validate a critical pointer reference before attempting to access or manipulate memory locations. This validation gap allows attackers to craft media files that, when processed by the system, cause the mediaserver to either enter an infinite loop or crash entirely, resulting in system instability. The flaw operates at the kernel level within the Android framework, specifically targeting the stagefright media processing library that handles various audio and video formats including mp4, 3gp, and other common multimedia containers. The lack of proper bounds checking and pointer validation creates an exploitable condition that can be triggered remotely through media file delivery.
The operational impact of this vulnerability extends beyond simple denial of service, as it can cause complete system instability and potential device reboots that disrupt user experience and compromise system availability. Attackers can remotely deliver malicious media files that, when opened or played by an Android device, trigger the vulnerable code path and cause the device to hang or reboot automatically. This creates a significant risk for users who may unknowingly encounter such media files through email attachments, web downloads, or other means of content delivery. The vulnerability affects the core media processing capabilities of Android devices, meaning that any application or service attempting to play media content could be exploited, including system applications, third-party media players, and web browsers. The remote nature of the attack means that users do not need to actively interact with the malicious content for the exploit to be triggered, making it particularly dangerous in mobile environments.
Mitigation strategies for CVE-2016-3899 focus primarily on applying the security patches released by Google for each affected Android version. Organizations and users should immediately update their Android devices to the latest security patches available for their specific version, particularly those released after September 2016. System administrators should implement network-level controls to prevent the delivery of potentially malicious media files through email systems and web proxies. The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and can be categorized under ATT&CK technique T1203, which involves legitimate credentials and system access. Additional protective measures include disabling automatic media playback in web browsers and email clients, implementing mobile device management policies that restrict media file handling, and conducting regular security assessments of media processing components. Network monitoring should be enhanced to detect unusual media file processing patterns that might indicate exploitation attempts, while security teams should maintain awareness of similar vulnerabilities in the stagefright framework that may require additional patching.