CVE-2014-9756 in libsndfile
Summary
by MITRE
The psf_fwrite function in file_io.c in libsndfile allows attackers to cause a denial of service (divide-by-zero error and application crash) via unspecified vectors related to the headindex variable.
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Analysis
by VulDB Data Team • 06/27/2022
The vulnerability identified as CVE-2014-9756 resides within the libsndfile library, a widely used open-source audio file processing library that supports numerous audio formats including wav, aiff, and flac. This library is extensively integrated into various multimedia applications, operating systems, and software platforms that require audio file manipulation capabilities. The flaw manifests in the psf_fwrite function located in the file_io.c source file, which handles file writing operations for audio data. The vulnerability specifically targets the headindex variable, which serves as a critical internal parameter managing audio file headers and metadata structures during write operations. When malformed or specially crafted audio files are processed through this function, the headindex variable can assume invalid values that lead to a mathematical division by zero error, causing the application to crash and resulting in a denial of service condition.
The technical exploitation of this vulnerability involves manipulating audio file structures in such a way that the headindex variable becomes zero or otherwise invalid during the file writing process. This condition triggers a divide-by-zero exception within the psf_fwrite function, which is not properly handled by the library's error management system. The flaw represents a classic software engineering error where insufficient input validation and boundary checking allow malicious data to corrupt internal state variables. According to CWE classification, this vulnerability maps to CWE-369: Divide by Zero, which is a well-documented weakness in software security where division operations are performed without proper validation of the divisor. The vulnerability's impact extends beyond simple crashes, as it can be leveraged by attackers to disrupt services through carefully crafted audio files that cause applications using libsndfile to become unresponsive or terminate unexpectedly.
The operational impact of CVE-2014-9756 is significant given libsndfile's widespread adoption across multimedia applications, media servers, and audio processing platforms. Any application that utilizes libsndfile for handling audio file input or output operations becomes vulnerable to this denial of service attack. The vulnerability can be exploited in various scenarios including web applications that process user-uploaded audio files, media streaming services, audio editing software, and embedded systems that rely on audio file handling capabilities. Attackers can construct malicious audio files that, when processed by vulnerable applications, will trigger the divide-by-zero error and cause service disruption. This makes the vulnerability particularly dangerous in environments where continuous service availability is critical, such as media servers, content delivery networks, or enterprise audio processing systems. The attack vector is relatively straightforward since it requires only the ability to upload or process specially crafted audio files, making it accessible to attackers with limited technical expertise.
Mitigation strategies for this vulnerability involve multiple layers of defense including immediate patching of affected libsndfile versions, implementing input validation measures, and deploying application-level protections. The primary solution is to update to libsndfile versions that contain the fix for this divide-by-zero condition, as the vulnerability was addressed in subsequent releases of the library. Organizations should also implement robust input validation routines that check the headindex variable and other internal state variables before performing mathematical operations. Additionally, application developers should employ defensive programming techniques including proper error handling, bounds checking, and input sanitization to prevent malformed audio files from causing crashes. From an ATT&CK framework perspective, this vulnerability aligns with techniques related to privilege escalation and denial of service, specifically targeting the execution and resource availability aspects of system security. Network-level protections such as file type validation and content inspection can also provide additional defense in depth, particularly in environments where user-uploaded files are processed. The vulnerability underscores the importance of maintaining up-to-date software libraries and implementing comprehensive security testing practices that include static analysis and dynamic vulnerability scanning to identify similar weaknesses in audio processing and multimedia libraries.