CVE-2016-3743 in Android
Summary
by MITRE
decoder/ih264d_api.c in mediaserver in Android 6.x before 2016-07-01 does not initialize certain data structures, which allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted media file, aka internal bug 27907656.
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Analysis
by VulDB Data Team • 02/21/2019
The vulnerability described in CVE-2016-3743 resides within the media server component of Android 6.x systems, specifically in the ih264d_api.c file responsible for handling H.264 video decoding operations. This flaw represents a critical security issue that affects the foundational multimedia processing capabilities of affected Android devices. The vulnerability stems from insufficient initialization of critical data structures during the video decoding process, creating exploitable conditions that can be leveraged by remote attackers to compromise system integrity. The affected component operates as part of the broader Android media framework, which processes various multimedia formats including video content from external sources, making it a prime target for exploitation through malicious media files.
The technical nature of this vulnerability can be categorized under CWE-457, which describes "Use of Uninitialized Variable" as the underlying cause of the issue. When the decoder fails to properly initialize certain data structures before processing incoming H.264 video streams, it creates memory corruption conditions that can be manipulated by attackers. The uninitialized variables may contain residual data from previous operations or random memory contents, leading to unpredictable behavior when the decoder attempts to interpret or execute operations based on this corrupted data. This memory corruption manifests as potential code execution privileges or denial of service conditions, depending on how the corrupted memory is subsequently utilized by the decoding process.
The operational impact of CVE-2016-3743 extends beyond simple system instability, as it provides attackers with remote code execution capabilities that can be leveraged across various attack vectors. An attacker could craft a malicious H.264 video file designed to trigger the uninitialized variable conditions during decoding, potentially allowing them to execute arbitrary code with the privileges of the media server process. This represents a significant escalation risk since the media server typically operates with elevated permissions to handle multimedia content, and successful exploitation could lead to complete system compromise. The vulnerability affects all Android 6.x devices released prior to the mentioned patch date, creating a substantial attack surface across numerous mobile devices and potentially impacting enterprise and consumer deployments.
Mitigation strategies for this vulnerability require immediate patch application as provided by Google through the Android Security Bulletins, which address the uninitialized variable issue in the decoder component. Organizations should prioritize deployment of the July 2016 security updates that specifically target this vulnerability, as the patch resolves the data structure initialization problems within the ih264d_api.c file. Additionally, network administrators should implement media content filtering mechanisms to prevent potentially malicious video files from reaching end-user devices, particularly in enterprise environments where device management and content control are more stringent. The vulnerability also highlights the importance of proper input validation and initialization practices in multimedia processing components, aligning with ATT&CK technique T1203 for "Exploitation for Client Execution" and emphasizing the need for secure coding practices in mobile platform components that handle external data processing.