CVE-2017-11547 in TiMidity++
Summary
by MITRE
The resample_gauss function in resample.c in TiMidity++ 2.14.0 allows remote attackers to cause a denial of service (heap-based buffer over-read) via a crafted mid file. NOTE: a crash might be relevant when using the --background option. NOTE: the TiMidity++ README.alsaseq documentation suggests a setuid-root installation.
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Analysis
by VulDB Data Team • 11/02/2019
The vulnerability identified as CVE-2017-11547 affects TiMidity++ version 2.14.0, a popular MIDI to audio file converter and synthesizer software. This issue resides within the resample_gauss function located in the resample.c source file, which handles audio resampling operations during MIDI file processing. The flaw manifests as a heap-based buffer over-read condition that occurs when processing specially crafted MIDI files, potentially leading to system instability and denial of service scenarios. The vulnerability is particularly concerning because TiMidity++ is often deployed in server environments where it may be configured with elevated privileges, including setuid-root installations as noted in the README.alsaseq documentation, which significantly amplifies the potential impact of this vulnerability.
The technical implementation of this vulnerability involves improper bounds checking within the resample_gauss function when handling audio sample data during the resampling process. When a maliciously crafted MIDI file is processed, the function fails to validate the boundaries of heap-allocated buffers, allowing an attacker to read memory beyond the allocated buffer limits. This heap-based buffer over-read can result in unpredictable behavior including program crashes, memory corruption, or potentially more severe consequences depending on the system configuration. The vulnerability is particularly dangerous when TiMidity++ is executed with the --background option, as this mode may be used in daemon processes where a crash could lead to persistent service unavailability. The flaw represents a classic buffer over-read vulnerability that falls under CWE-125, which specifically addresses out-of-bounds read conditions in software implementations.
The operational impact of CVE-2017-11547 extends beyond simple denial of service, as it can compromise the stability and availability of systems relying on TiMidity++ for audio processing. When the software is installed with setuid-root permissions, as recommended in the documentation, the vulnerability becomes even more critical because a successful exploitation could potentially allow attackers to gain elevated privileges or cause more widespread system instability. The vulnerability affects any system where TiMidity++ is used to process untrusted MIDI input, including web applications, audio processing servers, or multimedia systems that accept MIDI file uploads. The implications are particularly severe in environments where TiMidity++ operates continuously as a background service, as a single malicious MIDI file could cause sustained service disruption. This vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through resource exhaustion or system instability.
Mitigation strategies for this vulnerability should focus on immediate software updates to patched versions of TiMidity++ where the buffer over-read has been addressed through proper bounds checking and memory management. System administrators should avoid using setuid-root installations of TiMidity++ when possible, as this configuration significantly increases the attack surface and potential impact. Implementing proper input validation and sanitization for all MIDI file processing, along with restricting TiMidity++ execution to non-root privileges, provides additional layers of protection. Network segmentation and access controls should limit exposure to untrusted MIDI file processing, while monitoring systems should be configured to detect unusual crash patterns or resource consumption that may indicate exploitation attempts. Organizations should also consider implementing sandboxing or containerization for any audio processing services that handle untrusted input to limit the potential damage from successful exploitation attempts.