CVE-2017-7604 in HE-AAC+ Codec
Summary
by MITRE
au_channel.h in HE-AAC+ Codec (aka libaacplus) 2.0.2 has a left-shift undefined behavior issue, which might allow remote attackers to cause a denial of service (application crash) or possibly have unspecified other impact via a crafted audio file.
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Analysis
by VulDB Data Team • 08/27/2020
The vulnerability identified as CVE-2017-7604 resides within the HE-AAC+ Codec implementation known as libaacplus version 2.0.2, specifically in the au_channel.h component. This flaw represents a critical undefined behavior issue that manifests through improper left-shift operations within the audio decoding pipeline. The vulnerability stems from insufficient input validation and boundary checking when processing audio frame data, creating a scenario where maliciously crafted audio files can trigger unexpected program behavior during the decoding process. The affected software component operates as part of the Advanced Audio Coding standard implementation, specifically targeting high-efficiency audio compression formats that are widely used in multimedia applications and streaming services.
The technical root cause of this vulnerability lies in the undefined behavior associated with left-shift operations on integer values that exceed the maximum representable range for the target data type. When the codec processes audio frames containing malformed data, particularly in the channel configuration or frame header information, the left-shift operation can produce unpredictable results that lead to memory corruption or invalid memory access patterns. This undefined behavior creates a potential for arbitrary code execution or complete application termination, as the processor may encounter invalid memory addresses or corrupted program state during the decoding sequence. The vulnerability is classified under CWE-681, which specifically addresses "Incorrect Use of Excessive Integer Value" and represents a classic case of integer overflow or underflow that results in undefined program behavior. The flaw demonstrates characteristics consistent with the ATT&CK technique T1203, where adversaries manipulate program execution flow through input manipulation to cause system instability or unauthorized access.
The operational impact of CVE-2017-7604 extends beyond simple denial of service to potentially enable more sophisticated attack vectors. Remote attackers can exploit this vulnerability by delivering malicious audio files through various channels including web applications, media streaming platforms, or file sharing systems that utilize the affected libaacplus library. When a vulnerable application processes such crafted files, the undefined behavior can result in application crashes, system instability, or in more severe cases, potential privilege escalation if the affected software runs with elevated permissions. The vulnerability affects a broad range of multimedia applications that rely on HE-AAC+ decoding capabilities, including media players, streaming services, mobile applications, and embedded systems that handle audio content. The exploitability of this vulnerability is particularly concerning because it requires minimal user interaction beyond simply opening or playing the malicious audio file, making it a significant risk for both enterprise and consumer environments.
Mitigation strategies for CVE-2017-7604 should focus on immediate patching of affected systems and implementation of input validation controls. Organizations should prioritize updating to libaacplus version 2.0.3 or later, which contains the necessary fixes for the undefined left-shift behavior. Additionally, implementing strict input validation and sanitization measures can help prevent malformed audio data from reaching the vulnerable codec components. Network-level defenses should include content filtering mechanisms that can identify and block suspicious audio file patterns before they reach end-user applications. Security monitoring should be enhanced to detect unusual application behavior or crash patterns that may indicate exploitation attempts. The vulnerability highlights the importance of robust integer handling practices and proper boundary checking in multimedia codec implementations, emphasizing the need for adherence to secure coding standards and regular security assessments of third-party libraries used in audio processing pipelines. Organizations should also consider implementing application sandboxing and privilege separation techniques to limit the potential impact of successful exploitation attempts.