CVE-2018-11727 in libfsntfs
Summary
by MITRE
The libfsntfs_attribute_read_from_mft function in libfsntfs_attribute.c in libfsntfs through 2018-04-20 allows remote attackers to cause an information disclosure (heap-based buffer over-read) via a crafted ntfs file. NOTE: the vendor has disputed this as described in libyal/libfsntfs issue 8 on GitHub
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Analysis
by VulDB Data Team • 08/05/2024
The vulnerability identified as CVE-2018-11727 resides within the libfsntfs library, a component that provides filesystem support for NTFS file systems in various open-source projects. This library serves as a critical interface for applications that need to read and interpret NTFS filesystem structures, particularly in environments where cross-platform compatibility is essential. The specific function affected is libfsntfs_attribute_read_from_mft, which handles the reading of attribute data from the Master File Table, a fundamental structure in NTFS filesystems that contains metadata about all files and directories.
The technical flaw manifests as a heap-based buffer over-read condition that occurs when processing specially crafted NTFS files. This type of vulnerability falls under CWE-125, which describes out-of-bounds read conditions where an application reads data beyond the boundaries of a buffer. The flaw specifically occurs during the parsing of attribute records within the MFT, where insufficient bounds checking allows an attacker to craft malicious NTFS files that trigger memory access violations. When the library attempts to read attribute data from the MFT, it does not properly validate the size or structure of the incoming data, leading to reads beyond allocated memory boundaries.
The operational impact of this vulnerability extends beyond simple information disclosure, as it represents a potential vector for more serious attacks. Remote attackers who can influence the processing of NTFS files through vulnerable applications may exploit this to extract sensitive information from memory, potentially including credentials, cryptographic keys, or other confidential data. The heap-based nature of the vulnerability means that attackers could potentially manipulate memory layout to achieve more sophisticated attacks, though the immediate impact remains information disclosure. This vulnerability affects any application that relies on libfsntfs for NTFS file processing, including forensic tools, backup utilities, and cross-platform filesystem browsers.
The vendor has disputed this classification, indicating that the reported issue may not constitute a vulnerability in the traditional sense or may have been resolved through other means. This vendor dispute highlights the complexity of vulnerability assessment in open-source projects where the distinction between legitimate security issues and false positives can be ambiguous. The issue was documented in libyal/libfsntfs issue 8 on GitHub, which serves as a reference point for understanding how the community has approached this particular security concern. Organizations should consider implementing additional security controls beyond the vendor's stance, particularly when deploying applications that process untrusted NTFS files in production environments.
From an ATT&CK framework perspective, this vulnerability aligns with techniques related to information gathering and initial access phases. The information disclosure aspect maps to T1082 (System Information Discovery) and T1005 (Data from Local System), while the remote exploitation capability relates to T1190 (Exploit Public-Facing Application). The vulnerability demonstrates how seemingly benign file processing operations can become attack vectors when proper input validation is absent. Security practitioners should consider this in threat modeling exercises for systems that handle NTFS file processing, particularly in environments where untrusted file inputs are common. The vulnerability also underscores the importance of proper memory management and bounds checking in filesystem libraries, which are critical components in maintaining system security and integrity.