CVE-2016-0838 in Android
Summary
by MITRE
Sonivox 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 2016-04-01 does not check for a negative number of samples, which allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted media file, related to arm-wt-22k/lib_src/eas_wtengine.c and arm-wt-22k/lib_src/eas_wtsynth.c, aka internal bug 26366256.
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Analysis
by VulDB Data Team • 07/12/2022
The vulnerability described in CVE-2016-0838 resides within the Sonivox media processing component of Android operating systems, specifically affecting versions prior to the mentioned security patches. This flaw manifests in the mediaserver process which handles multimedia file processing, making it a critical target for remote exploitation. The vulnerability stems from insufficient input validation within the audio synthesis engine, particularly in the handling of sample counts within audio file processing routines. The affected code paths are located in arm-wt-22k/lib_src/eas_wtengine.c and arm-wt-22k/lib_src/eas_wtsynth.c, which are part of the embedded audio synthesis library responsible for processing various audio formats including those used in telephony and multimedia applications.
The technical flaw represents a classic integer underflow or negative value handling issue that falls under CWE-191, which deals with integer underflows and overflows. The vulnerability occurs when the media server processes audio files that contain malformed sample count values, specifically negative numbers that should never occur in legitimate audio file structures. When the system attempts to process these negative sample counts, it leads to improper memory allocation calculations and subsequent memory corruption. This memory corruption can manifest in two primary ways: either as a controlled memory access violation that allows attackers to execute arbitrary code, or as an uncontrolled memory corruption that results in denial of service through system crashes or heap corruption. The vulnerability is particularly dangerous because it can be triggered remotely through crafted media files, making it exploitable via various attack vectors including email attachments, web downloads, or file sharing applications.
The operational impact of this vulnerability is severe across the affected Android versions, as it provides attackers with a reliable method to compromise devices running these vulnerable versions. The attack surface is broad since any application that processes audio files through the mediaserver component could potentially be exploited, including email clients, web browsers, file managers, and multimedia applications. The vulnerability enables both remote code execution and denial of service capabilities, making it attractive to threat actors seeking to compromise Android devices. From an attack perspective, this vulnerability maps to multiple ATT&CK techniques including T1059 for command and control execution and T1489 for denial of service. The exploitation requires minimal privileges and can be automated, making it particularly dangerous in mass exploitation scenarios. The memory corruption resulting from negative sample count processing can lead to predictable memory layout corruption, potentially enabling attackers to achieve arbitrary code execution through carefully crafted payloads.
Mitigation strategies for this vulnerability should focus on immediate patching of affected Android versions to the security releases that address the integer underflow issue in the Sonivox audio processing libraries. Organizations should implement comprehensive mobile device management policies that ensure all Android devices receive security updates promptly. Network-based mitigations can include content filtering and sandboxing of media file processing, though these approaches are less effective than direct patching. The vulnerability also highlights the importance of input validation in multimedia processing libraries, suggesting that similar checks should be implemented across all audio and video processing components. Additionally, security monitoring should include detection of abnormal memory access patterns and potential exploitation attempts through the mediaserver process, as these indicators may precede successful exploitation attempts. System administrators should also consider implementing network segmentation to limit the potential impact of successful exploitation, particularly in enterprise environments where multiple Android devices may be connected to the same network infrastructure.