CVE-2018-19890 in Freeware Advanced Audio Coder
Summary
by MITRE
An invalid memory address dereference was discovered in the huffcode function (libfaac/huff2.c) in Freeware Advanced Audio Coder (FAAC) 1.29.9.2. The vulnerability causes a segmentation fault and application crash, which leads to denial of service in the book 2 case.
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Analysis
by VulDB Data Team • 06/13/2023
The vulnerability identified as CVE-2018-19890 represents a critical memory safety issue within the Freeware Advanced Audio Coder library version 1.29.9.2. This flaw exists in the huffcode function located in the libfaac/huff2.c source file, which is part of the FAAC audio encoding library widely used for processing audio content in various multimedia applications and streaming platforms. The vulnerability manifests as an invalid memory address dereference that occurs during the Huffman coding process, a fundamental component of audio compression algorithms. The specific context of this issue involves the book 2 case handling within the Huffman encoding logic where the software attempts to access memory locations that have not been properly validated or allocated, creating a dangerous condition that can be exploited by malicious actors.
The technical implementation of this vulnerability stems from inadequate input validation within the huffcode function where the software fails to properly check array bounds or memory pointers before attempting to dereference them. When processing audio data through the book 2 case scenario, the function encounters a situation where it attempts to access memory at an invalid address, typically caused by uninitialized variables, improper buffer handling, or incorrect pointer arithmetic within the Huffman coding algorithm implementation. This type of flaw falls under the CWE-476 category of NULL Pointer Dereference, though specifically manifests as an invalid memory address dereference that can occur even when pointers are not null but point to invalid memory locations. The vulnerability creates a segmentation fault that terminates the application process, making it a classic example of a denial of service condition that can be triggered by malformed audio input data.
The operational impact of CVE-2018-19890 extends beyond simple application crashes to potentially compromise the availability and reliability of systems that depend on FAAC for audio processing. Any application or service utilizing this library for audio encoding, transcoding, or streaming operations becomes vulnerable to denial of service attacks when processing maliciously crafted audio files. The vulnerability is particularly concerning in server environments, media processing pipelines, and streaming platforms where continuous availability is critical, as a single malicious audio file could cause complete service disruption. Attackers could exploit this weakness by submitting specially crafted audio content that triggers the specific code path leading to the invalid memory dereference, resulting in system crashes that require manual intervention to restore service. This vulnerability aligns with ATT&CK technique T1499.004 for Network Denial of Service and demonstrates how seemingly benign media processing libraries can become attack vectors when memory safety issues are present.
Mitigation strategies for CVE-2018-19890 should prioritize immediate software updates to the latest version of FAAC where the memory safety issues have been addressed through proper input validation and memory management practices. Organizations should implement comprehensive input sanitization measures for all audio content processed through systems utilizing FAAC, including validation of file formats, size limits, and content integrity checks before processing. Additionally, deploying application sandboxing techniques and implementing robust error handling mechanisms can help contain the impact of such vulnerabilities by preventing crashes from affecting broader system availability. System administrators should also consider implementing monitoring and alerting for unusual application behavior or crash patterns that might indicate exploitation attempts, while maintaining regular security assessments of multimedia processing pipelines to identify similar memory safety issues in other components of their audio processing infrastructure.