CVE-2017-1000249 in File
Summary
by MITRE
An issue in file() was introduced in commit 9611f31313a93aa036389c5f3b15eea53510d4d1 (Oct 2016) lets an attacker overwrite a fixed 20 bytes stack buffer with a specially crafted .notes section in an ELF binary. This was fixed in commit 35c94dc6acc418f1ad7f6241a6680e5327495793 (Aug 2017).
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Analysis
by VulDB Data Team • 12/28/2022
The vulnerability identified as CVE-2017-1000249 represents a critical stack buffer overflow flaw within the file command utility, which is widely used for identifying file types by examining their contents. This issue emerged from a specific code change introduced in October 2016 through commit 9611f31313a93aa036389c5f3b15eea53510d4d1, demonstrating how seemingly minor modifications to software can introduce severe security risks that persist for months before detection. The file command, part of the fileutils package commonly found on Unix-like systems, serves as a fundamental tool for system administrators and security professionals to determine file formats and types, making its vulnerability particularly concerning for widespread exploitation.
The technical flaw manifests through improper handling of the .notes section within ELF (Executable and Linkable Format) binaries, which are the standard executable format for Unix-like operating systems. When processing a specially crafted ELF binary, the file utility attempts to read metadata from the .notes section and stores this information in a fixed 20-byte stack buffer without adequate bounds checking. This classic buffer overflow vulnerability allows an attacker to overwrite adjacent stack memory, potentially leading to arbitrary code execution or system compromise. The vulnerability falls under CWE-121, which specifically addresses stack-based buffer overflow conditions, and demonstrates the dangers of insufficient input validation in security-critical utilities that process untrusted data.
The operational impact of this vulnerability extends far beyond simple exploitation, as the file command is frequently invoked by various system processes and security tools. Attackers can leverage this flaw by creating malicious ELF binaries with crafted .notes sections that trigger the buffer overflow when the file utility processes them, potentially compromising systems where the utility is executed with elevated privileges or in automated security scanning workflows. This vulnerability aligns with ATT&CK technique T1059.007, which covers the use of file command for system reconnaissance and information gathering, as attackers can use the compromised utility to gain additional system information or escalate privileges. The vulnerability's persistence from October 2016 through August 2017 indicates a significant window during which systems remained exposed to potential exploitation, particularly affecting systems that regularly process or scan ELF files from untrusted sources.
The remediation for CVE-2017-1000249 was addressed through commit 35c94dc6acc418f1ad7f6241a6680e5327495793, which implemented proper bounds checking for the .notes section processing within the file utility. This fix demonstrates the importance of input validation and bounds checking in security-critical code, particularly in utilities that process external data without proper sanitization. System administrators should ensure that all affected systems have been updated to versions containing this fix, as the vulnerability represents a significant risk to system integrity and confidentiality. The vulnerability serves as a cautionary example of how even widely trusted system utilities can contain critical flaws that require continuous security monitoring and timely patching to maintain system security posture.