CVE-2016-2429 in Android
Summary
by MITRE
libFLAC/stream_decoder.c 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 2016-05-01 does not prevent free operations on uninitialized memory, which allows remote attackers to execute arbitrary code or cause a denial of service (heap memory corruption) via a crafted media file, aka internal bug 27211885.
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Analysis
by VulDB Data Team • 07/27/2022
The vulnerability identified as CVE-2016-2429 represents a critical heap memory corruption issue within the libFLAC stream decoder component of Android's mediaserver application. This flaw exists in multiple Android versions including 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 specified date, making it a widespread concern across the Android ecosystem. The vulnerability stems from improper handling of memory operations during the processing of FLAC audio files, specifically when the decoder attempts to perform free operations on memory that has not been properly initialized. This memory management error creates a dangerous condition where attackers can manipulate the decoder's behavior through carefully crafted malicious media files.
The technical implementation of this vulnerability involves a classic heap corruption scenario where uninitialized memory pointers are subject to free operations without proper validation or initialization checks. When the mediaserver processes a specially crafted FLAC file, the stream decoder fails to properly initialize memory structures before attempting to free them, leading to unpredictable memory states. This flaw allows attackers to manipulate the heap layout and potentially overwrite critical memory regions, creating opportunities for arbitrary code execution. The vulnerability is particularly dangerous because it operates at the system level within the mediaserver process, which typically runs with elevated privileges and has access to various system resources. According to CWE standards, this corresponds to CWE-459, which describes incomplete cleanup issues, and CWE-125, which addresses out-of-bounds read conditions that can lead to memory corruption.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it provides attackers with potential paths to achieve arbitrary code execution on affected Android devices. Remote attackers can exploit this vulnerability by delivering maliciously crafted FLAC media files through various attack vectors including email attachments, web downloads, or malicious applications. Once executed, the heap corruption can result in system crashes, application instability, or more severely, allow attackers to escalate privileges and gain unauthorized access to device resources. The vulnerability's presence in the mediaserver component means that any media file processed by the system could potentially be exploited, making it particularly dangerous for mobile environments where users frequently interact with untrusted media content. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and code injection, with potential TTPs including execution through media processing and system compromise through memory corruption attacks.
Mitigation strategies for CVE-2016-2429 should prioritize immediate patching of affected Android versions, with organizations and users upgrading to patched releases that address the uninitialized memory handling in the libFLAC decoder. The recommended approach includes implementing proper memory initialization checks before any free operations, adding bounds checking to prevent out-of-bounds memory access, and enhancing input validation for all media file formats processed by the mediaserver. Additionally, system administrators should consider implementing network-based security controls to filter potentially malicious media files, while application developers should ensure proper error handling and memory management practices in their media processing libraries. The vulnerability highlights the importance of robust memory management practices in system-level components and underscores the need for comprehensive security testing of media processing libraries to prevent similar issues from arising in the future.