CVE-2018-20359 in Freeware Advanced Audio Decoder
Summary
by MITRE
An invalid memory address dereference was discovered in the sbrDecodeSingleFramePS function of libfaad/sbr_dec.c in Freeware Advanced Audio Decoder 2 (FAAD2) 2.8.8. The vulnerability causes a segmentation fault and application crash, which leads to denial of service.
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Analysis
by VulDB Data Team • 06/20/2023
The vulnerability identified as CVE-2018-20359 represents a critical memory safety issue within the Freeware Advanced Audio Decoder 2 version 2.8.8 library. This flaw manifests in the sbrDecodeSingleFramePS function located within the libfaad/sbr_dec.c source file, where an invalid memory address dereference occurs during audio frame processing. The affected library serves as a core component for decoding advanced audio formats including aac and mp4 audio content across numerous multimedia applications and operating systems. The vulnerability specifically targets the spectral band replication decoding process which is essential for reconstructing high-quality audio signals from compressed data streams.
The technical nature of this flaw stems from inadequate input validation and memory management within the audio decoding pipeline. When processing malformed or specially crafted audio files, the sbrDecodeSingleFramePS function attempts to access memory locations that have not been properly allocated or validated, resulting in a segmentation fault. This type of memory corruption vulnerability falls under the CWE-476 category of NULL Pointer Dereference, though specifically manifests as an invalid memory address dereference. The vulnerability demonstrates characteristics consistent with improper handling of edge cases in audio data parsing, where the decoder fails to properly validate the structure and boundaries of incoming spectral band replication data before attempting to access memory regions.
The operational impact of CVE-2018-20359 extends beyond simple application crashes to potentially enable more sophisticated attack vectors. While the immediate effect results in denial of service through segmentation faults and application termination, this vulnerability could be exploited by malicious actors to achieve remote code execution under certain conditions. The vulnerability affects any system utilizing FAAD2 2.8.8 or earlier versions for audio processing, including media players, streaming applications, web browsers, and embedded systems. The widespread adoption of FAAD2 across various platforms increases the potential attack surface significantly, making this vulnerability particularly concerning for security professionals. Attackers could craft malicious audio files designed to trigger this specific memory corruption during playback, potentially leading to system instability or unauthorized code execution.
Mitigation strategies for this vulnerability require immediate patching of affected systems to upgrade to FAAD2 versions 2.8.9 or later where the memory access validation has been properly implemented. System administrators should conduct comprehensive inventory assessments to identify all installations of FAAD2 2.8.8 or earlier versions across their infrastructure. The recommended approach involves implementing strict input validation mechanisms and memory bounds checking within audio processing pipelines, aligning with ATT&CK technique T1203 for legitimate credential access and T1059 for command and scripting interpreter usage. Organizations should also consider implementing network segmentation and application whitelisting to limit the potential impact of exploitation attempts. Additionally, deploying intrusion detection systems capable of monitoring for suspicious audio file processing patterns and implementing proper error handling mechanisms within applications using FAAD2 can provide additional layers of protection. Regular security updates and vulnerability assessments should be prioritized to maintain system integrity against similar memory safety issues that may emerge in other components of the audio processing stack.