CVE-2004-2303 in mtools
Summary
by MITRE
mtools mformat before 3.9.9 when installed setuid root creates files with world-readable and world-writable permissions which allows local users to read and overwrite files.
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Analysis
by VulDB Data Team • 12/10/2024
The vulnerability identified as CVE-2004-2303 affects the mtools package version 3.9.9 and earlier, specifically within the mformat utility when executed with setuid root privileges. This security flaw represents a critical misconfiguration in file permission handling that directly undermines the principle of least privilege and creates significant attack vectors for local adversaries. The mformat utility is designed to format floppy disk images or create filesystems on various storage devices, but its improper handling of file permissions when running with elevated privileges creates a persistent security weakness.
The technical root cause of this vulnerability lies in the improper implementation of file permission management within the mformat utility. When executed with setuid root privileges, the utility fails to properly restrict file permissions on created files, resulting in world-readable and world-writable permissions being applied to files that should maintain restricted access. This misconfiguration stems from inadequate permission handling code that does not properly reset file creation masks or apply appropriate umask values during file operations. The flaw manifests as a failure to enforce proper access controls that should normally be maintained by the setuid mechanism, allowing any local user to manipulate files that should remain protected.
The operational impact of this vulnerability extends beyond simple privilege escalation as it creates persistent backdoors and data integrity risks within systems. Local users can exploit this weakness to read sensitive files that they would normally not have access to, potentially exposing confidential information, configuration data, or system secrets. Additionally, the world-writable permissions enable attackers to overwrite critical files, leading to potential data corruption, system instability, or the installation of malicious code that persists across system reboots. This vulnerability effectively undermines the security model of the system by allowing unprivileged users to gain unauthorized access to resources that should remain protected. The impact is particularly severe in multi-user environments where multiple users share the same system resources.
Mitigation strategies for this vulnerability require immediate remediation through patching the mtools package to version 3.9.9 or later, which contains the necessary permission handling fixes. System administrators should also implement comprehensive monitoring of setuid binary usage and file permission changes to detect potential exploitation attempts. The principle of least privilege should be enforced by removing unnecessary setuid permissions from utilities that do not require elevated privileges for their operation. Additionally, implementing proper file system auditing and access control mechanisms can help detect unauthorized file modifications. This vulnerability aligns with CWE-276, which addresses improper file permissions, and represents a classic example of privilege escalation through improper access control implementation. Organizations should also consider implementing the ATT&CK technique T1068, which involves exploiting local privilege escalation vulnerabilities, as this represents a fundamental attack vector that adversaries can leverage for persistent system compromise. The remediation process should include thorough system audits to identify any other setuid utilities with similar permission handling issues and ensure comprehensive security posture maintenance.