CVE-2004-0233 in Utempter
Summary
by MITRE
Utempter allows device names that contain .. (dot dot) directory traversal sequences, which allows local users to overwrite arbitrary files via a symlink attack on device names in combination with an application that trusts the utmp or wtmp files.
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Analysis
by VulDB Data Team • 12/16/2024
The vulnerability identified as CVE-2004-0233 resides within the utempter utility, a component designed to manage user login records in Unix-like operating systems. This flaw represents a classic directory traversal vulnerability that exploits the improper handling of device names containing ".." sequences. The utempter utility is responsible for maintaining utmp and wtmp files that track user login sessions, making it a critical component in system security monitoring and authentication processes. When device names are processed without proper validation, attackers can manipulate the system's understanding of file paths through carefully crafted symbolic links.
The technical exploitation mechanism leverages the fundamental weakness in path resolution where ".." sequences are not properly sanitized or rejected during device name processing. This vulnerability specifically targets the trust model inherent in applications that rely on utmp and wtmp files for authentication decisions or session tracking. Attackers can create symbolic links with device names containing directory traversal sequences, allowing them to manipulate the file system in ways that bypass normal access controls. The flaw operates at the file system level where the utempter utility fails to validate that device names do not contain potentially dangerous path traversal sequences, thereby enabling attackers to redirect file operations to arbitrary locations on the system.
The operational impact of this vulnerability extends beyond simple file overwrites to encompass potential privilege escalation and system compromise. Local users with minimal privileges can exploit this weakness to modify critical system files, potentially gaining elevated access or corrupting system integrity. The vulnerability affects the trust relationships between system components, as applications that depend on utmp and wtmp files for security decisions may be tricked into operating on maliciously crafted data. This creates a chain reaction where compromised session tracking can lead to broader system compromise, especially in environments where login monitoring and access control are tightly integrated. The attack vector is particularly insidious because it requires no network access and can be executed entirely within the local system environment.
Mitigation strategies for CVE-2004-0233 focus on implementing proper input validation and sanitization of device names within the utempter utility. System administrators should ensure that all device names containing ".." sequences are rejected during processing, and that symbolic link resolution is properly validated before file operations are executed. The vulnerability aligns with CWE-22 Directory Traversal and CWE-345 Insufficient Verification of Data Authenticity, representing a failure in both path validation and trust model implementation. From an ATT&CK perspective, this vulnerability maps to T1068 Local Privilege Escalation and T1548 Abuse of Systemd Service or T1566 Phishing, as attackers can use it to manipulate system files and potentially escalate privileges. Organizations should implement regular system updates, conduct thorough security audits of system utilities, and establish monitoring for suspicious file access patterns in utmp and wtmp files to detect potential exploitation attempts.