CVE-2018-20361 in Freeware Advanced Audio Decoder
Summary
by MITRE
An invalid memory address dereference was discovered in the hf_assembly function of libfaad/sbr_hfadj.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-2018-20361 represents a critical memory safety issue within the Freeware Advanced Audio Decoder 2 version 2.8.8 library implementation. This flaw manifests in the hf_assembly function located within the libfaad/sbr_hfadj.c source file, where improper memory handling creates conditions that can lead to system instability and service disruption. The affected library serves as a core component for decoding advanced audio formats including aac and aacp files, making it widely utilized across various media applications and platforms.
The technical nature of this vulnerability stems from an invalid memory address dereference that occurs during the processing of specific audio data streams. When the hf_assembly function encounters malformed or unexpected input parameters, it attempts to access memory locations that are either uninitialized, freed, or otherwise invalid. This improper memory access pattern directly violates fundamental memory safety principles and results in immediate system termination through segmentation fault exceptions. The flaw operates at the intersection of buffer management and control flow integrity, where the decoder fails to properly validate input parameters before executing memory operations.
The operational impact of CVE-2018-20361 extends beyond simple application crashes to encompass broader system availability concerns. Since FAAD2 is integrated into numerous multimedia applications, operating systems, and embedded devices, exploitation of this vulnerability can trigger widespread denial of service conditions. Attackers can craft malicious audio files that, when processed by vulnerable applications, will cause immediate system termination and prevent legitimate audio playback functionality. This makes the vulnerability particularly dangerous in environments where continuous audio processing is critical, such as media servers, streaming platforms, or embedded systems with limited recovery mechanisms.
From a cybersecurity perspective, this vulnerability aligns with CWE-476 which categorizes null pointer dereference conditions, though specifically manifests as invalid memory address dereference. The flaw demonstrates characteristics consistent with the attack pattern described in MITRE ATT&CK framework under T1499.004 for network denial of service attacks, where adversaries leverage software vulnerabilities to disrupt service availability. The vulnerability represents a classic example of how multimedia processing libraries can become attack vectors when insufficient input validation and memory safety checks are implemented. Organizations utilizing FAAD2 should prioritize immediate patching and implementation of input sanitization measures to prevent exploitation.
Mitigation strategies for CVE-2018-20361 require both immediate remediation and long-term architectural improvements. The most direct solution involves upgrading to FAAD2 versions that contain fixed implementations of the hf_assembly function with proper memory validation and bounds checking. System administrators should implement input filtering mechanisms that validate audio file headers and structure before processing, preventing malformed data from reaching the vulnerable decoder functions. Additionally, application developers should incorporate defensive programming practices including proper error handling, memory allocation validation, and input parameter sanitization to reduce the attack surface. Regular security assessments of multimedia processing components and implementation of automated vulnerability scanning tools can help identify similar memory safety issues before they can be exploited in production environments.