CVE-2000-0375 in FreeBSD
Summary
by MITRE
The kernel in FreeBSD 3.2 follows symbolic links when it creates core dump files, which allows local attackers to modify arbitrary files.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 02/13/2017
The vulnerability described in CVE-2000-0375 represents a critical security flaw in the FreeBSD 3.2 kernel implementation that directly impacts how core dump files are handled during system crashes or process termination. This issue stems from the kernel's improper handling of symbolic link resolution when creating core dump files, creating an exploitable condition that allows local attackers to manipulate the file system in unintended ways. The flaw specifically manifests when the kernel encounters symbolic links during the core dump creation process, leading to potential unauthorized file modifications.
The technical root cause of this vulnerability lies in the kernel's failure to properly validate or resolve symbolic links when determining the target location for core dump files. When a process terminates abnormally, the kernel typically creates a core dump file to capture the process memory state for debugging purposes. However, in FreeBSD 3.2, the kernel's core dump mechanism does not adequately sanitize symbolic link paths, allowing an attacker who controls a symbolic link to redirect the core dump creation to a location of their choosing. This behavior violates fundamental security principles and creates a privilege escalation vector.
From an operational perspective, this vulnerability enables local attackers to modify arbitrary files on the system by manipulating symbolic links in directories where core dumps might be created. The impact extends beyond simple file modification to potentially allow attackers to overwrite critical system files, inject malicious code, or corrupt important data structures. Attackers can exploit this by creating symbolic links that point to sensitive files and then triggering a process termination that results in core dump creation, effectively bypassing normal file system permissions and access controls.
The vulnerability aligns with CWE-59 and CWE-22 categories from the Common Weakness Enumeration, specifically addressing improper link resolution in file operations and path traversal issues. From the MITRE ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and persistence mechanisms, as attackers can leverage the core dump functionality to gain elevated privileges or maintain access through file system modifications. The local nature of this attack means that exploitation requires only user-level access, making it particularly dangerous as it can be exploited by any user with access to the system.
Mitigation strategies for this vulnerability include upgrading to a patched version of FreeBSD that properly resolves symbolic links during core dump creation, implementing proper file system permissions and restrictions on core dump directories, and monitoring for unusual core dump creation patterns. System administrators should also consider disabling core dump creation for sensitive processes or implementing additional security controls such as file integrity monitoring to detect unauthorized modifications. The recommended approach involves applying the official FreeBSD security patches that address the symbolic link handling in kernel core dump functionality, ensuring that the kernel properly validates all file paths before creating core dump files.