CVE-2018-20360 in Freeware Advanced Audio Decoder
Summary
by MITRE
An invalid memory address dereference was discovered in the sbr_process_channel 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-2018-20360 represents a critical memory safety issue within the Freeware Advanced Audio Decoder 2 version 2.8.8 library. This flaw exists in the sbr_process_channel function located within the libfaad/sbr_dec.c source file, which is part of the core audio decoding infrastructure used by numerous applications and systems for processing advanced audio formats. The vulnerability manifests as an invalid memory address dereference that occurs during the processing of specific audio data streams, particularly those involving spectral band replication techniques commonly used in high-quality audio compression standards.
The technical nature of this vulnerability aligns with CWE-476 which describes NULL pointer dereference conditions, though in this case the issue involves invalid memory addresses rather than null pointers specifically. When the sbr_process_channel function processes malformed or specially crafted audio input data, it attempts to access memory locations that have not been properly validated or allocated, resulting in a segmentation fault. This type of memory corruption vulnerability is particularly dangerous because it can be exploited by attackers who craft malicious audio files designed to trigger the specific code path that leads to the invalid memory access, causing the targeted application to terminate unexpectedly and crash.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it can be leveraged by malicious actors to disrupt audio processing services, media players, and applications that rely on FAAD2 for audio decoding. Systems utilizing this library may experience complete service interruption when processing specially crafted audio content, potentially affecting media streaming platforms, audio editing software, broadcast systems, and embedded devices that incorporate FAAD2 for audio handling. The vulnerability's exploitation requires minimal privileges and can be executed through standard audio file processing, making it particularly attractive to threat actors seeking to disrupt services or create persistent availability issues for affected systems.
Mitigation strategies for CVE-2018-20360 should prioritize immediate software updates to FAAD2 version 2.8.9 or later, which contains the necessary patches to address the memory access validation issues in the sbr_process_channel function. Organizations should implement comprehensive input validation mechanisms that sanitize audio data before processing, particularly for files originating from untrusted sources. Network security controls including content filtering and audio file inspection can provide additional layers of protection by identifying and blocking potentially malicious audio content. Security monitoring should include detection of application crashes and segmentation faults related to audio processing components, while system hardening measures such as address space layout randomization and stack canaries can help mitigate potential exploitation attempts. The vulnerability demonstrates the importance of maintaining up-to-date multimedia libraries and implementing robust memory safety practices in audio processing applications, as outlined in the ATT&CK framework's software exploitation tactics that emphasize the targeting of memory corruption vulnerabilities in multimedia libraries and codecs.