CVE-2016-3872 in Android
Summary
by MITRE
Buffer overflow in codecs/on2/dec/SoftVPX.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 allows attackers to gain privileges via a crafted application, aka internal bug 29421675.
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Analysis
by VulDB Data Team • 09/15/2022
The vulnerability identified as CVE-2016-3872 represents a critical buffer overflow flaw within the Android media processing framework that affects multiple versions of the Android operating system. This vulnerability exists in the libstagefright library's media server component, specifically within the SoftVPX.cpp file that handles VPX video codec decoding operations. The flaw resides in the codecs/on2/dec/SoftVPX.cpp module which processes video content using the VPX codec standard, commonly employed in webm and other multimedia formats. The vulnerability was classified under CWE-121 as a stack-based buffer overflow, where insufficient bounds checking allows an attacker to overwrite adjacent memory locations in the application's memory space.
The technical exploitation of this vulnerability occurs when a malicious application presents specially crafted media content to the Android media server through the libstagefright framework. During the decoding process of VPX video streams, the application fails to properly validate the size of incoming data before copying it into fixed-size buffers. This allows an attacker to overflow the allocated buffer space and overwrite adjacent memory regions including return addresses, function pointers, and other critical control data. The vulnerability specifically impacts Android versions 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, indicating a widespread exposure across the Android platform's media processing stack.
The operational impact of this privilege escalation vulnerability is severe and directly aligns with ATT&CK technique T1068 which describes privilege escalation through software vulnerabilities. An attacker who successfully exploits this vulnerability can gain elevated privileges within the Android system, potentially allowing them to execute arbitrary code with the privileges of the media server process. This elevated access enables the attacker to bypass normal security restrictions, access protected system resources, and potentially compromise the entire device. The media server typically runs with significant system privileges to handle multimedia processing, making this a particularly dangerous vector for attackers seeking persistent access to Android devices. The vulnerability's exposure across multiple Android versions indicates a fundamental flaw in the media processing architecture that required immediate patching across the Android ecosystem.
Mitigation strategies for CVE-2016-3872 focus on both immediate patching and defensive measures within the Android platform. The primary solution involves applying the security patches released by Google for affected Android versions, which include bounds checking improvements and memory validation routines in the libstagefright library. Organizations should implement comprehensive patch management programs to ensure all Android devices receive the necessary updates promptly. Additional defensive measures include network-level filtering to block suspicious media content, application sandboxing to limit media processing capabilities, and monitoring for anomalous behavior patterns that might indicate exploitation attempts. The vulnerability also highlights the importance of secure coding practices in multimedia frameworks, particularly around buffer management and input validation. Security professionals should consider implementing runtime protections such as address space layout randomization and stack canaries to make exploitation more difficult even if the underlying vulnerability persists. The incident underscores the critical need for continuous security assessment of media processing components and adherence to secure coding standards throughout the Android platform's development lifecycle.