CVE-2011-2915 in libmodplug
Summary
by MITRE
Off-by-one error in the CSoundFile::ReadAMS2 function in src/load_ams.cpp in libmodplug before 0.8.8.4 allows remote attackers to cause a denial of service (memory corruption) and possibly execute arbitrary code via a crafted AMS file with a large number of instruments.
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Analysis
by VulDB Data Team • 12/03/2021
The vulnerability identified as CVE-2011-2915 represents a critical off-by-one error within the libmodplug library's audio file processing functionality. This flaw exists specifically in the CSoundFile::ReadAMS2 function located in the src/load_ams.cpp source file, affecting all versions prior to 0.8.8.4. The issue manifests when processing AMS (Audio Module Studio) files, which are proprietary audio formats used in music composition and playback applications. The vulnerability stems from improper bounds checking during the parsing of instrument data structures within these files, creating a condition where memory access exceeds allocated boundaries.
The technical nature of this vulnerability aligns with CWE-129, which describes improper validation of array indices, and CWE-125, which addresses reading memory outside of allocated bounds. When an attacker crafts a malicious AMS file containing an excessive number of instruments, the off-by-one error causes the application to read or write beyond the intended memory boundaries. This memory corruption can lead to unpredictable behavior including application crashes, denial of service conditions, or potentially more severe consequences such as arbitrary code execution. The vulnerability operates through the standard file parsing pathway that applications use to load audio modules, making it particularly dangerous as it can be triggered simply by opening or processing a specially crafted file.
The operational impact of this vulnerability extends across numerous applications that depend on libmodplug for audio file handling, particularly those involved in music production, gaming, and multimedia applications. Attackers can leverage this flaw by distributing malicious AMS files through various vectors including email attachments, file sharing networks, or compromised websites. When victims open these files with vulnerable applications, the memory corruption can cause immediate application termination or, in more sophisticated attacks, provide a foothold for code execution. The vulnerability is particularly concerning because AMS files are commonly used in mod player applications and music creation software, making the attack surface quite broad across both consumer and professional audio applications.
Mitigation strategies for CVE-2011-2915 primarily focus on updating to libmodplug version 0.8.8.4 or later, which contains the necessary patches to address the bounds checking issue. System administrators should prioritize patching all affected applications that utilize libmodplug, particularly those handling user-supplied audio files. Additional protective measures include implementing strict file validation procedures, using sandboxing techniques for audio file processing, and deploying network-based intrusion detection systems that can identify suspicious file patterns. The vulnerability also highlights the importance of proper input validation and bounds checking in audio processing libraries, as demonstrated by the ATT&CK framework's emphasis on defense in depth strategies for preventing memory corruption exploits. Organizations should also consider implementing automated vulnerability scanning tools to identify and remediate older versions of libmodplug across their software ecosystems.