CVE-2005-4604 in MTink
Summary
by MITRE
Buffer overflow in MTink in the printer-filters-utils package allows local users to execute arbitrary code via a long HOME environment variable.
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Analysis
by VulDB Data Team • 07/27/2019
The vulnerability described in CVE-2005-4604 represents a classic buffer overflow flaw within the MTink component of the printer-filters-utils package, a critical security issue that enables local privilege escalation through environment variable manipulation. This vulnerability specifically targets the handling of the HOME environment variable, where insufficient bounds checking allows attackers to overflow a fixed-size buffer and potentially overwrite adjacent memory locations. The flaw exists in the printer filtering utilities that process print jobs and manage printer configurations, making it particularly dangerous in multi-user environments where local attackers could exploit this weakness to execute arbitrary code with elevated privileges. The vulnerability demonstrates poor input validation practices in system-level utilities that handle user environment variables, creating a pathway for privilege escalation attacks that align with common attack patterns documented in the attack mitigation framework.
The technical implementation of this buffer overflow stems from inadequate string handling within the MTink utility, which processes print job data and interacts with system environment variables during printer configuration operations. When a local user sets an excessively long HOME environment variable, the application fails to properly validate the input length before copying it into a predetermined buffer space, resulting in memory corruption that can be exploited to overwrite return addresses or function pointers. This type of vulnerability maps directly to CWE-121, which describes stack-based buffer overflow conditions, and represents a fundamental flaw in memory management practices. The attack vector specifically targets local users who can manipulate environment variables, making it a local privilege escalation vulnerability that does not require network access or remote exploitation capabilities. The flaw demonstrates how seemingly innocuous environment variable handling can create significant security risks in system utilities that operate with elevated privileges.
The operational impact of this vulnerability extends beyond simple code execution, as it enables attackers to gain unauthorized access to system resources and potentially escalate privileges to root level access. Local users who exploit this vulnerability can manipulate the printer filtering system to execute malicious code, potentially leading to complete system compromise and unauthorized access to sensitive data. The vulnerability affects systems running the affected printer-filters-utils package where MTink is used for print job processing, particularly impacting Unix-based systems and Linux distributions that utilize this utility for printer management. Organizations with multiple users sharing printer systems are especially vulnerable, as any local user could potentially exploit this weakness to gain elevated privileges and access restricted system resources. This type of vulnerability represents a significant concern for enterprise environments where printer systems are integrated with broader network infrastructure and where local privilege escalation could provide attackers with persistent access to critical systems.
Mitigation strategies for this vulnerability require immediate patching of the affected printer-filters-utils package, which would include implementing proper bounds checking for environment variable handling and ensuring that input validation prevents buffer overflows. System administrators should also implement environment variable restrictions and monitoring to detect unusual HOME variable lengths that might indicate exploitation attempts. The remediation approach should include reviewing all system utilities that handle environment variables and implementing secure coding practices that prevent buffer overflows through proper input validation and memory management. Additionally, organizations should consider implementing privilege separation mechanisms and monitoring for suspicious print job processing activities that could indicate exploitation attempts. This vulnerability highlights the importance of secure coding practices in system utilities and the necessity of thorough input validation, particularly in components that operate with elevated privileges and handle user-provided data. The fix should align with security best practices outlined in the Common Weakness Enumeration standards and should be implemented as part of comprehensive vulnerability management programs that address both known and emerging threats in system security.