CVE-2016-2483 in Android
Summary
by MITRE
The mm-video-v4l2 venc component 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 2016-06-01 mishandles a buffer count, which allows attackers to gain privileges via a crafted application, as demonstrated by obtaining Signature or SignatureOrSystem access, aka internal bug 27662502.
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Analysis
by VulDB Data Team • 01/18/2019
The vulnerability identified as CVE-2016-2483 resides within the mm-video-v4l2 venc component of the mediaserver process in various Android versions, specifically affecting 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 the 2016-06-01 security patch release. This issue represents a critical privilege escalation flaw that enables attackers to execute malicious applications capable of obtaining elevated system privileges. The vulnerability stems from improper buffer count handling within the video encoding component, which operates as part of the Android multimedia framework and is responsible for video compression and encoding operations. The mediaserver process runs with elevated privileges and is essential for multimedia functionality across the Android operating system, making it a prime target for attackers seeking system-level access.
The technical flaw manifests when the venc component fails to properly validate or manage buffer counts during video encoding operations, creating a condition where an attacker-controlled application can manipulate buffer parameters to trigger unexpected behavior in the underlying multimedia subsystem. This buffer count manipulation allows for memory corruption or control flow hijacking within the mediaserver process, enabling attackers to bypass normal access controls and escalate privileges to the Signature or SignatureOrSystem level. The vulnerability specifically enables attackers to gain access that would normally require system-level signatures or privileged applications, effectively allowing them to execute code with the highest available privileges within the Android system. This flaw operates under the Common Weakness Enumeration CWE-121, which categorizes buffer overflow conditions, and aligns with ATT&CK technique T1068, privilege escalation through exploitation of system vulnerabilities.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with access to sensitive system functionalities that could enable further exploitation or data exfiltration. Once an attacker achieves Signature or SignatureOrSystem access, they can install malicious applications with system-level privileges, modify system files, access protected data, and potentially establish persistent backdoors. The vulnerability is particularly concerning because it requires no user interaction beyond installing a malicious application, making it a zero-click privilege escalation vector. The affected mediaserver component is integral to Android multimedia operations, meaning that exploitation could occur during normal video encoding activities, such as when users capture videos or process multimedia content through various applications. Security researchers have noted that this vulnerability demonstrates the critical importance of proper buffer management in system-level processes, as even seemingly benign multimedia operations can serve as attack vectors for sophisticated privilege escalation attacks.
Mitigation strategies for CVE-2016-2483 primarily involve applying the relevant security patches released by Google as part of their regular Android security updates, specifically targeting the identified Android versions and their respective patch levels. Organizations and users should ensure that their Android devices receive all available security updates, particularly those addressing the mediaserver and multimedia subsystem vulnerabilities. Additionally, implementing application whitelisting policies and restricting the installation of unsigned or untrusted applications can help prevent exploitation of this vulnerability. Network administrators should monitor for suspicious application installations and maintain updated threat intelligence regarding similar vulnerabilities in multimedia frameworks. The vulnerability highlights the importance of secure coding practices in system-level components and emphasizes the need for comprehensive input validation and buffer management in multimedia processing libraries. Organizations should also consider implementing mobile device management solutions that can automatically enforce security policies and ensure timely patch deployment across enterprise devices.