CVE-2001-0119 in getty_ps
Summary
by MITRE
getty_ps 2.0.7j allows local users to overwrite arbitrary files via a symlink attack.
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Analysis
by VulDB Data Team • 04/30/2019
The vulnerability identified as CVE-2001-0119 affects getty_ps version 2.0.7j, a system utility commonly used in Unix-like operating systems for managing terminal login processes. This flaw represents a classic symlink attack vulnerability that enables local users to manipulate file operations through malicious symbolic link creation. The issue stems from insufficient validation of symbolic links during file operations, creating a path traversal scenario that can be exploited by attackers with local access to the system. The vulnerability specifically impacts systems where getty_ps is used to handle terminal sessions and login processes, making it particularly relevant in multi-user environments where local privilege escalation opportunities exist.
The technical implementation of this vulnerability occurs when getty_ps performs file operations without properly verifying the target of symbolic links before executing write operations. An attacker can create malicious symbolic links in directories where getty_ps expects to write temporary or configuration files, causing the utility to write data to unintended locations. This type of attack falls under the category of time-of-check to time-of-use race conditions, where the system checks for file permissions or existence at one point in time but the actual file operation occurs later when the symbolic link may have been altered by the attacker. The flaw demonstrates poor input validation and inadequate security controls in file system operations, which aligns with CWE-367, the weakness category for time-of-check to time-of-use race conditions.
The operational impact of this vulnerability extends beyond simple file overwrites, as it can be leveraged for privilege escalation and persistent system compromise. Local attackers can use this vulnerability to overwrite critical system files, configuration data, or even binaries that are executed by the getty_ps utility, potentially leading to complete system compromise. The attack vector requires local system access but does not necessitate network connectivity, making it particularly dangerous in environments where physical or account access is possible. This vulnerability represents a significant concern for system administrators who must ensure proper file system permissions and avoid insecure temporary file handling practices. The exploitability of this vulnerability is enhanced in environments where multiple users have access to shared directories or where system utilities are not properly secured against symbolic link manipulation.
Mitigation strategies for CVE-2001-0119 should focus on immediate patching of the getty_ps utility to the latest secure version that addresses the symbolic link handling flaw. System administrators should implement proper file system permissions and ensure that temporary directories used by getty_ps are not writable by untrusted users. The principle of least privilege should be enforced by restricting write access to directories where the utility operates and by using absolute paths instead of relative paths when handling file operations. Additionally, monitoring for suspicious file creation patterns and symbolic link manipulation can help detect potential exploitation attempts. Organizations should also consider implementing automated patch management systems to ensure timely deployment of security updates. This vulnerability highlights the importance of secure coding practices and proper validation of file system operations, particularly in system utilities that handle user authentication and terminal sessions, as outlined in various security frameworks including those referenced in the ATT&CK framework for system compromise techniques.