CVE-2019-8906 in libmagic
Summary
by MITRE
do_core_note in readelf.c in libmagic.a in file 5.35 has an out-of-bounds read because memcpy is misused.
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Analysis
by VulDB Data Team • 07/11/2023
The vulnerability identified as CVE-2019-8906 represents a critical out-of-bounds read condition within the file command's libmagic library implementation. This flaw exists in the do_core_note function located in readelf.c within the libmagic.a archive of file version 5.35. The issue stems from improper usage of the memcpy function which allows unauthorized memory access beyond the allocated buffer boundaries. The vulnerability manifests when the file command processes specially crafted binary files that trigger the core note parsing functionality, potentially leading to information disclosure or system instability.
The technical root cause of this vulnerability aligns with CWE-125, which specifically addresses out-of-bounds read conditions in software implementations. The improper memcpy usage demonstrates a classic buffer over-read vulnerability where the program attempts to copy data beyond the legitimate memory boundaries of a target buffer. This misconfiguration allows attackers to access memory locations that should remain protected, potentially exposing sensitive data from adjacent memory regions. The vulnerability operates at the application level within the file command's magic file processing subsystem, making it particularly dangerous as it can be triggered by simple file analysis operations.
From an operational impact perspective, this vulnerability presents significant security risks to systems that rely on the file command for automated file type detection and analysis. Attackers could exploit this flaw by crafting malicious binary files that, when processed by the file command, would trigger the out-of-bounds read condition. The consequences could include unauthorized data exposure, system crashes, or potentially more severe outcomes depending on the execution environment. The vulnerability affects systems where the file command is used in automated scanning processes, web applications, or security tools that depend on accurate file type identification.
The attack surface for this vulnerability extends beyond simple local exploitation to include remote code execution scenarios in certain contexts. According to ATT&CK framework reference T1059.007, this vulnerability could enable adversaries to leverage command execution capabilities through file analysis tools. Organizations using the file command in security scanning, malware analysis, or automated content processing systems face particular risk. The vulnerability's exploitation potential increases when the file command is integrated into larger security frameworks or used in environments where untrusted files are regularly analyzed. Mitigation strategies should focus on input validation, proper memory boundary checking, and immediate patching of affected file versions.
Effective remediation requires updating to file version 5.36 or later where the memcpy usage has been corrected to properly validate buffer boundaries before memory operations. System administrators should implement comprehensive patch management procedures to address this vulnerability across all affected systems. Additional protective measures include implementing strict file type validation, restricting file command execution in privileged contexts, and monitoring for unusual file analysis patterns that might indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of proper memory management practices in security-sensitive applications and highlights the need for thorough code review processes to identify similar out-of-bounds access conditions in widely-used system utilities.