CVE-2016-3765 in Android
Summary
by MITRE
decoder/impeg2d_bitstream.c in mediaserver in Android 6.x before 2016-07-01 allows attackers to obtain sensitive information from process memory or cause a denial of service (out-of-bounds read) via a crafted application, aka internal bug 28168413.
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Analysis
by VulDB Data Team • 02/22/2019
The vulnerability identified as CVE-2016-3765 resides within the decoder/impeg2d_bitstream.c component of the mediaserver service in Android 6.x operating systems, specifically affecting versions prior to the 2016-07-01 security patch release. This flaw represents a critical security weakness that manifests through improper input validation during MPEG-2 video decoding operations, creating potential pathways for malicious exploitation. The vulnerability is particularly concerning as it affects the core media processing infrastructure that handles multimedia content across Android devices, making it a prime target for attackers seeking to compromise device security or disrupt system functionality.
The technical implementation of this vulnerability stems from an out-of-bounds read condition occurring in the MPEG-2 bitstream decoder logic. When processing crafted malicious video files, the decoder fails to properly validate buffer boundaries during bitstream parsing operations, allowing attackers to manipulate memory access patterns that exceed allocated buffer limits. This memory corruption issue originates from insufficient input sanitization within the video decoding pipeline, where the application does not adequately verify the length or structure of incoming bitstream data before attempting to parse it. The flaw specifically manifests in the impeg2d_bitstream.c source file, which handles the decoding of MPEG-2 compressed video data streams, making it particularly dangerous as it can be triggered through standard media playback operations.
From an operational perspective, this vulnerability presents dual threat vectors that significantly impact system security and stability. Attackers can leverage this weakness to either extract sensitive information from process memory through information disclosure attacks or to induce denial of service conditions by triggering system crashes through controlled out-of-bounds memory reads. The potential for information disclosure means that malicious actors could access confidential data stored in memory segments, including cryptographic keys, user credentials, or other sensitive application data that remains in memory during media processing operations. The denial of service component creates system instability that could render devices unusable or force applications to terminate unexpectedly, impacting user experience and potentially providing attackers with additional attack vectors.
The security implications extend beyond immediate exploitation as this vulnerability represents a classic example of a buffer over-read condition that aligns with CWE-125, which specifically addresses out-of-bounds read vulnerabilities in software systems. This flaw demonstrates how media processing components can become attack surfaces for privilege escalation and information gathering attacks, particularly when dealing with untrusted input data from external sources. The vulnerability's impact is amplified by its location within the mediaserver process, which operates with elevated privileges and has access to various system resources, making successful exploitation potentially devastating for device security. From an attacker's perspective, this vulnerability fits within the ATT&CK framework under the T1059 technique category, specifically targeting process injection and memory manipulation methods to achieve unauthorized access to system resources.
Mitigation strategies for this vulnerability require immediate system updates and patch deployment to address the root cause within the Android media processing framework. Organizations should prioritize applying the security patches released by Google in the 2016-07-01 update cycle, which specifically address the bitstream parsing logic in the MPEG-2 decoder. Additionally, implementing network-level controls to restrict media file downloads from untrusted sources can provide additional defense-in-depth measures. System administrators should also consider implementing monitoring solutions to detect unusual memory access patterns or process behavior that might indicate exploitation attempts. The vulnerability highlights the importance of robust input validation and memory safety practices in multimedia processing components, emphasizing the need for comprehensive security testing of media handling code to prevent similar issues from arising in future implementations.