CVE-2017-9223 in Freeware Advanced Audio Decoder
Summary
by MITRE
The mp4ff_read_stts function in common/mp4ff/mp4atom.c in Freeware Advanced Audio Decoder 2 (FAAD2) 2.7 allows remote attackers to cause a denial of service (invalid memory read and application crash) via a crafted mp4 file.
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Analysis
by VulDB Data Team • 10/20/2019
The vulnerability identified as CVE-2017-9223 resides within the Freeware Advanced Audio Decoder 2 version 2.7, specifically in the mp4ff_read_stts function located in the common/mp4ff/mp4atom.c file. This flaw represents a critical security issue that can be exploited by remote attackers to execute a denial of service attack against systems utilizing this audio decoding library. The vulnerability manifests when the application processes a specially crafted mp4 file that contains malformed timestamp data, leading to an invalid memory read operation that ultimately causes the application to crash.
This vulnerability falls under the category of improper input validation and memory safety issues, which are commonly classified under CWE-125: Out-of-bounds Read and CWE-248: Uncaught Exception. The mp4ff_read_stts function fails to properly validate the structure and content of timestamp entries within the mp4 file format, particularly when handling the stts (sample table) atom. When encountering malformed or unexpected data in the timestamp structure, the function attempts to read memory locations that are either invalid or not properly allocated, resulting in a segmentation fault or memory access violation. The attack vector is particularly concerning as it requires no local privileges or special user interaction beyond the simple act of opening or processing the malicious file.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be leveraged in various attack scenarios that target systems using FAAD2 for audio processing. Network-based attacks can exploit this vulnerability by delivering malicious mp4 files through web applications, email attachments, or file sharing services that utilize FAAD2 for media processing. The vulnerability affects not only standalone applications but also web browsers, media players, and server applications that incorporate FAAD2 as part of their audio decoding capabilities. From an ATT&CK framework perspective, this vulnerability maps to T1499.004: Endpoint Denial of Service and T1595.001: Network Denial of Service, as it enables adversaries to disrupt services through memory corruption techniques.
Mitigation strategies for CVE-2017-9223 should focus on immediate patching of affected systems and implementation of input validation measures. Organizations should prioritize updating to FAAD2 version 2.8 or later, where this vulnerability has been addressed through proper bounds checking and memory validation. Additionally, defensive programming practices should be implemented to sanitize all input data before processing, including validation of file headers, atom structures, and timestamp entries within mp4 files. Network-level defenses such as content filtering and file type validation can help prevent exploitation by blocking suspicious mp4 files before they reach vulnerable applications. System administrators should also consider implementing application whitelisting and sandboxing techniques to limit the potential impact of exploitation, particularly in environments where multiple applications may be processing multimedia content. The vulnerability demonstrates the importance of robust memory safety practices in multimedia processing libraries and highlights the need for comprehensive testing of edge cases in file format parsing functions.