CVE-2000-0880 in LPPlus
Summary
by MITRE
LPPlus creates the lpdprocess file with world-writeable permissions, which allows local users to kill arbitrary processes by specifying an alternate process ID and using the setuid dcclpdshut program to kill the process that was specified in the lpdprocess file.
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Analysis
by VulDB Data Team • 01/19/2025
The vulnerability described in CVE-2000-0880 represents a critical privilege escalation flaw within the LPPlus printing system implementation. This issue stems from improper permission handling during the creation of system files, specifically the lpdprocess file that is generated during the printing process. The fundamental problem lies in the system's failure to properly secure temporary files, creating an environment where local attackers can manipulate system processes through deliberate file manipulation. The vulnerability is particularly concerning because it leverages existing system utilities with elevated privileges to execute malicious actions, effectively bypassing normal access controls that should protect critical system processes.
The technical implementation of this vulnerability involves the interaction between multiple system components including the setuid dcclpdshut program and the LPPlus printing subsystem. When the lpdprocess file is created, it is assigned world-writable permissions, which violates fundamental security principles outlined in the CWE-732 category for Incorrect Permission Assignment for Critical Resource. This misconfiguration allows any local user to modify the file contents, specifically the process identifier that is stored within it. The dcclpdshut program, which is designed to shut down the printing daemon, operates with elevated privileges due to its setuid bit, but it trusts the information contained in the lpdprocess file without proper validation. This trust relationship creates a path for privilege escalation where an attacker can manipulate the process ID value to target any running process on the system.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system stability and security compromise. Attackers can leverage this weakness to kill arbitrary processes, potentially targeting critical system services or user applications. The vulnerability essentially provides a mechanism for process termination that bypasses normal user access controls and system security policies. From an adversarial perspective, this creates opportunities for denial-of-service attacks, system disruption, or even more sophisticated attacks where the termination of specific processes could be used as part of a broader exploitation strategy. The attack vector is particularly insidious because it requires no network access and can be executed entirely from the local system, making it difficult to detect through traditional network monitoring approaches.
The security implications of this vulnerability align with several ATT&CK framework techniques including privilege escalation and defense evasion. The technique T1068 specifically addresses local privilege escalation through the exploitation of system vulnerabilities, while T1562.001 covers defense evasion through the manipulation of system processes. Organizations running affected systems face significant risk as this vulnerability can be exploited by any local user, including potentially compromised accounts or unauthorized individuals with physical access to the system. The remediation approach must address both the immediate permission issue and the broader design flaw in how the system handles temporary files. Proper mitigation requires setting appropriate file permissions, implementing proper input validation for process identifiers, and potentially redesigning the shutdown mechanism to avoid trusting user-controllable data sources.
This vulnerability demonstrates the importance of secure coding practices and proper privilege management in system-level software. The root cause lies in the failure to implement proper access controls during file creation, a fundamental security principle that should be applied to all temporary files and system resources. The issue highlights the dangers of relying on setuid programs without proper input validation and underscores the need for principle of least privilege implementations. Organizations should implement regular security audits of system files and permissions, particularly focusing on setuid binaries and their associated temporary file handling. The vulnerability also emphasizes the importance of proper system hardening practices and the need for security-conscious development practices that consider all possible attack vectors, including those that involve manipulation of system resources and processes.