CVE-2000-0604 in Linux
Summary
by MITRE
gkermit in Red Hat Linux is improperly installed with setgid uucp, which allows local users to modify files owned by uucp.
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Analysis
by VulDB Data Team • 04/14/2019
The vulnerability described in CVE-2000-0604 represents a classic privilege escalation issue affecting the gkermit utility in Red Hat Linux systems. This flaw stems from improper file permissions during the installation process where the gkermit binary is configured with the setgid bit set to the uucp group. The uucp group typically has specific permissions and privileges within Unix-like systems, particularly related to serial communication and modem access. When a binary is installed with setgid permissions, it executes with the privileges of the group that owns the file rather than the user who runs it, creating potential security implications when combined with other system weaknesses.
The technical implementation of this vulnerability allows local users to exploit the setgid uucp permission by leveraging the gkermit utility's functionality to modify files that are owned by the uucp group. This creates a path for privilege escalation attacks where ordinary users can gain elevated access to system resources that should normally be restricted. The vulnerability specifically affects systems where gkermit is installed with the setgid uucp bit set, making it a direct target for local privilege escalation attempts. The flaw operates under the principle of least privilege violation, where the system grants more permissions than necessary for normal operation, creating opportunities for malicious actors to exploit these excess privileges.
From an operational standpoint, this vulnerability poses significant risks to system security and integrity, particularly in multi-user environments where local access is possible. Attackers can potentially modify critical system files, configuration data, or communication logs that are owned by the uucp group, leading to data corruption, unauthorized access, or system compromise. The impact extends beyond simple file modification as it can enable attackers to manipulate serial communication parameters, access modem configurations, or interfere with uucp-related network services. This vulnerability aligns with CWE-276, which addresses improper file permissions, and represents a classic example of how improper privilege management can lead to security breaches.
The mitigation strategies for this vulnerability involve immediate remediation through proper file permission management and system hardening practices. System administrators should ensure that the gkermit binary is not installed with unnecessary setgid permissions, particularly when those permissions grant access to sensitive system resources. The recommended approach includes removing the setgid bit from the gkermit binary or reconfiguring the system to use appropriate privilege levels for the utility. Additionally, implementing proper access controls and monitoring for unauthorized modifications to system binaries helps detect potential exploitation attempts. This vulnerability demonstrates the importance of following security best practices such as those outlined in the NIST Cybersecurity Framework and aligns with ATT&CK technique T1068, which covers privilege escalation through local exploitation of system vulnerabilities. Regular security audits and permission reviews should be conducted to prevent similar issues from arising in other system utilities or applications.