CVE-2016-7424 in libav
Summary
by MITRE
The put_no_rnd_pixels8_xy2_mmx function in x86/rnd_template.c in libav 11.7 and earlier allows remote attackers to cause a denial of service (NULL pointer dereference and crash) via a crafted MP3 file.
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Analysis
by VulDB Data Team • 09/19/2024
The vulnerability identified as CVE-2016-7424 represents a critical denial of service flaw within the libav multimedia framework version 11.7 and earlier. This issue specifically affects the put_no_rnd_pixels8_xy2_mmx function located in the x86/rnd_template.c source file, which is part of the libav library used extensively for handling audio and video processing tasks across numerous applications and systems. The vulnerability arises from insufficient input validation and error handling within the MP3 decoding pipeline, creating a scenario where maliciously crafted MP3 files can trigger unexpected behavior in the affected software components.
The technical exploitation of this vulnerability occurs through a NULL pointer dereference condition that manifests when the put_no_rnd_pixels8_xy2_mmx function processes specially crafted MP3 data. This function is designed to handle pixel manipulation operations in x86 architecture using MMX instruction sets for optimized performance. When a malformed MP3 file is processed, the function fails to properly validate pointer references, leading to a situation where a NULL pointer is dereferenced during the decoding process. This results in an immediate crash of the application or system component utilizing libav for media processing, effectively creating a denial of service condition that can be remotely triggered by attackers who control the input media file.
The operational impact of CVE-2016-7424 extends beyond simple service disruption, as it can affect a wide range of applications that depend on libav for multimedia processing capabilities. Systems utilizing this library include media servers, content delivery networks, streaming platforms, and various multimedia applications that handle user-uploaded content. The vulnerability's remote exploitability means that attackers can potentially compromise service availability without requiring local system access, making it particularly dangerous in web-facing applications and services. This type of vulnerability aligns with CWE-476, which categorizes NULL pointer dereference conditions as a common weakness that can lead to application crashes and potential information disclosure.
From a cybersecurity perspective, this vulnerability demonstrates the importance of robust input validation in multimedia processing libraries, as highlighted by ATT&CK technique T1203 which involves gaining access through the execution of malicious code. The flaw represents a classic example of how seemingly minor issues in low-level code can have significant security implications, particularly in widely used open source libraries that form the foundation of many multimedia applications. The vulnerability affects not only the direct users of libav but also any system that relies on applications built on top of this library, creating a cascading effect that can impact entire ecosystems of software that depend on multimedia processing capabilities.
Mitigation strategies for CVE-2016-7424 primarily involve updating to libav version 11.8 or later, where the vulnerability has been patched through improved input validation and proper pointer handling mechanisms. Organizations should also implement additional protective measures such as input sanitization for media files, network segmentation to limit exposure, and regular security assessments of multimedia processing components. The fix typically involves adding proper null checks before pointer dereference operations and ensuring that all input parameters are validated before being processed by the affected functions, thereby preventing the conditions that lead to the NULL pointer dereference and subsequent crash.