CVE-2016-3871 in Android
Summary
by MITRE
Multiple buffer overflows in codecs/mp3dec/SoftMP3.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 allow attackers to gain privileges via a crafted application, aka internal bug 29422022.
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Analysis
by VulDB Data Team • 09/15/2022
The vulnerability described in CVE-2016-3871 represents a critical buffer overflow issue within the Android media processing framework that affects multiple versions of the Android operating system. This flaw exists in the libstagefright library's MP3 decoder component, specifically in the codecs/mp3dec/SoftMP3.cpp file, which is responsible for handling multimedia content processing within the mediaserver daemon. The vulnerability stems from inadequate input validation and memory management practices when processing specially crafted MP3 files, creating opportunities for attackers to exploit memory corruption conditions that can lead to privilege escalation.
The technical implementation of this vulnerability involves a classic buffer overflow condition that occurs during the decoding process of MP3 audio files. When the SoftMP3.cpp component processes malformed or specially crafted MP3 data, it fails to properly validate the size of incoming data buffers, leading to memory corruption that can be leveraged to overwrite adjacent memory locations. This type of vulnerability is classified as CWE-121, which specifically addresses stack-based buffer overflow conditions, and it demonstrates the dangerous combination of improper input validation and insufficient memory bounds checking. The flaw is particularly concerning because it operates within the mediaserver process, which runs with elevated privileges and has access to system resources and capabilities that normal applications cannot access directly.
The operational impact of this vulnerability extends far beyond simple local privilege escalation, as it provides attackers with the ability to execute arbitrary code with system-level privileges. The mediaserver daemon in Android systems is designed to handle multimedia processing tasks for various applications, making it a prime target for exploitation since it frequently processes user-supplied content. Attackers can craft malicious MP3 files that, when played or processed by the affected Android versions, trigger the buffer overflow condition and allow for privilege elevation. This capability directly maps to ATT&CK technique T1068, which describes the use of local privilege escalation to gain system-level access, and represents a significant threat to Android device security. The vulnerability affects a broad range of Android versions, including 4.x through 7.0, making it particularly dangerous as it impacts numerous devices that may not have received timely security updates.
Mitigation strategies for this vulnerability require immediate patching of affected Android versions, as the only reliable solution is the application of security updates from Google that address the buffer overflow conditions in the libstagefright library. Organizations and users should ensure that all Android devices are updated to the latest security patches, particularly those released in September 2016, which specifically addressed this issue. Additionally, administrators should implement monitoring for suspicious media processing activities and consider network-level controls to prevent the execution of untrusted media content. The vulnerability's presence in the core media processing framework emphasizes the importance of comprehensive security testing and validation of multimedia components, particularly those that handle user-supplied data without adequate sanitization. Security teams should also consider implementing application whitelisting policies and restricting media processing capabilities in environments where the risk of exploitation is elevated.