CVE-2007-6720 in libmikmod
Summary
by MITRE
libmikmod 3.1.9 through 3.2.0, as used by MikMod, SDL-mixer, and possibly other products, relies on the channel count of the last loaded song, rather than the currently playing song, for certain playback calculations, which allows user-assisted attackers to cause a denial of service (application crash) by loading multiple songs (aka MOD files) with different numbers of channels.
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Analysis
by VulDB Data Team • 08/04/2021
The vulnerability identified as CVE-2007-6720 represents a critical buffer management flaw within libmikmod library versions 3.1.9 through 3.2.0 that affects multimedia applications relying on this audio library for module file playback. This issue stems from improper handling of channel count information during the playback process, specifically when transitioning between different musical compositions within the same application session. The flaw manifests when applications load multiple module files with varying channel configurations, creating a scenario where the library maintains state information from the last loaded song rather than dynamically adapting to the currently active song's requirements.
The technical implementation of this vulnerability occurs at the memory management level where libmikmod fails to properly validate and update channel count parameters during song transitions. When a new module file is loaded, the library incorrectly retains the channel count from the previous song in its internal data structures, leading to miscalculations during playback operations. This mismanagement results in buffer overflows or underflows when the application attempts to allocate or access memory regions based on the outdated channel count information. The vulnerability is classified under CWE-129 as an insufficient input validation, specifically concerning buffer size calculations that depend on incorrect data state.
The operational impact of this vulnerability extends beyond simple application instability to potentially enable more sophisticated attack vectors. An attacker can exploit this weakness by crafting specially designed module files with different channel configurations, then sequentially loading them into an application using libmikmod. The resulting application crash occurs during playback when the system attempts to process audio data using the incorrect channel count, leading to denial of service conditions that can disrupt legitimate user operations. This vulnerability particularly affects multimedia applications, game engines, and audio processing software that utilize libmikmod for MOD file playback, making it a significant concern for entertainment and multimedia software vendors.
Mitigation strategies for CVE-2007-6720 require immediate updates to libmikmod library versions that have addressed this channel count handling issue through proper state management and dynamic parameter validation. System administrators and software maintainers should prioritize patching affected applications to ensure they use libmikmod versions 3.2.1 or later where the channel count calculation logic has been corrected. Additionally, implementing proper input validation mechanisms within applications that utilize libmikmod can provide defense-in-depth protection, requiring that all loaded module files undergo channel count verification before playback initiation. The ATT&CK framework categorizes this vulnerability under T1499.004 as a denial of service attack through resource exhaustion, though the specific implementation involves memory corruption rather than traditional resource depletion techniques. Organizations should also consider implementing runtime monitoring and application sandboxing to detect and prevent exploitation attempts targeting this specific vulnerability pattern.