CVE-2000-0163 in FreeBSD
Summary
by MITRE
asmon and ascpu in FreeBSD allow local users to gain root privileges via a configuration file.
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Analysis
by VulDB Data Team • 09/09/2024
The vulnerability identified as CVE-2000-0163 affects FreeBSD systems and specifically targets the asmon and ascpu utilities which are part of the system monitoring and performance analysis tools. These utilities are designed to provide system administrators with detailed information about system performance and resource utilization. The flaw exists in how these programs handle configuration files, creating a privilege escalation opportunity for local attackers who can manipulate the configuration files to execute arbitrary code with root privileges. This represents a classic local privilege escalation vulnerability where unprivileged users can leverage system configuration weaknesses to gain administrative access.
The technical implementation of this vulnerability stems from inadequate input validation and privilege handling within the asmon and ascpu applications. When these utilities process their configuration files, they fail to properly validate file permissions or ownership before executing code or commands specified in the configuration. This allows a local user to create or modify the configuration file in such a way that when the utility runs with elevated privileges, it executes malicious code with root permissions. The vulnerability is particularly concerning because it operates at the system level where configuration files are often processed with elevated privileges to ensure proper system monitoring functionality. This flaw aligns with CWE-276 which describes inadequate privileges or permissions, specifically focusing on improper file permissions that lead to privilege escalation.
From an operational perspective, this vulnerability presents a significant risk to FreeBSD systems as it allows any local user to potentially gain complete system control without requiring authentication or specialized attack vectors. The attack requires only local access to the system, making it particularly dangerous in environments where multiple users have access to the same machine. The impact extends beyond simple privilege escalation as it provides attackers with complete control over system resources, potentially enabling further attacks such as data exfiltration, system compromise, or the installation of persistent backdoors. This vulnerability demonstrates how seemingly benign system monitoring tools can become attack vectors when proper security controls are not implemented in their configuration handling mechanisms.
Mitigation strategies for CVE-2000-0163 should focus on immediate patching of affected FreeBSD systems to address the underlying configuration file handling issues. System administrators should ensure that the asmon and ascpu utilities are updated to versions that properly validate configuration file permissions and ownership before processing. Additionally, implementing proper file permission controls on configuration files used by these utilities can provide defense in depth. The system should enforce that configuration files are owned by root and have restricted permissions to prevent unauthorized modification. Organizations should also consider implementing monitoring for unauthorized changes to system configuration files and establish proper access controls to limit local user privileges where possible. This vulnerability highlights the importance of privilege separation and secure configuration management practices, aligning with ATT&CK technique T1068 which covers privilege escalation through local exploits. Regular security audits of system utilities and their configuration handling should be conducted to identify similar vulnerabilities in other system components that may present similar privilege escalation risks.