CVE-2017-11119 in Nosefart
Summary
by MITRE
The chk_mem_access function in cpu/nes6502/nes6502.c in libnosefart.a in Nosefart 2.9-mls allows remote attackers to cause a denial of service (invalid memory read and application crash) via a crafted nsf file.
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Analysis
by VulDB Data Team • 11/02/2019
The vulnerability identified as CVE-2017-11119 represents a critical memory access flaw within the Nosefart 2.9-mls library implementation that affects the handling of NSF (Nintendo Sound Format) files. This issue resides in the chk_mem_access function located within the cpu/nes6502/nes6502.c file of the libnosefart.a library, which serves as the core emulation engine for NES 6502 processor instructions in the Nosefart framework. The vulnerability manifests when processing specially crafted NSF files that contain malformed memory access patterns, leading to invalid memory reads and subsequent application crashes that result in a denial of service condition.
The technical exploitation of this vulnerability stems from insufficient input validation and memory boundary checking within the chk_mem_access function. When the NES 6502 processor emulation encounters improperly formatted NSF files, the function fails to properly validate memory access ranges and addresses, allowing attackers to craft malicious NSF content that triggers invalid memory reads. This flaw operates at the intersection of software emulation and file format parsing, where the emulation engine attempts to access memory locations that either do not exist or are not properly allocated, resulting in segmentation faults and application termination. The vulnerability is classified as a buffer over-read condition under CWE-125 and represents a classic example of improper input validation that leads to memory corruption.
The operational impact of this vulnerability extends beyond simple denial of service, as it creates potential attack vectors for remote exploitation within applications that utilize the Nosefart library for audio file processing. Any system or application that accepts NSF files for playback, conversion, or analysis becomes a potential target for this attack, particularly those running on embedded systems or gaming emulators where the library is integrated. The vulnerability affects both desktop and mobile implementations that rely on the libnosefart.a library for NES audio format processing, making it particularly concerning for gaming applications, music player software, and retro gaming emulators. From an attack perspective, this vulnerability aligns with ATT&CK technique T1203 by enabling adversaries to cause system instability and denial of service conditions that can disrupt normal operations.
Mitigation strategies for CVE-2017-11119 should focus on implementing robust input validation and memory boundary checking within the chk_mem_access function to prevent invalid memory access patterns. The most effective approach involves adding comprehensive validation routines that verify memory access ranges against valid address boundaries before any memory operations are performed. Additionally, developers should implement proper error handling and graceful degradation mechanisms that prevent application crashes when malformed NSF files are encountered. The fix should include bounds checking for all memory access operations, proper validation of NSF file headers and data structures, and implementation of defensive programming practices that prevent unauthorized memory access. System administrators should also consider implementing file type validation and sandboxing mechanisms for applications that process NSF files to limit the potential impact of exploitation. The vulnerability highlights the importance of thorough input validation in emulation environments and demonstrates how seemingly benign file format parsing can become a critical security concern when proper memory management practices are not implemented.