CVE-2004-0158 in lbreakout2
Summary
by MITRE
Buffer overflow in lbreakout2 allows local users to gain games group privileges via a large HOME environment variable to (1) editor.c, (2) theme.c, (3) manager.c, (4) config.c, (5) game.c, (6) levels.c, or (7) main.c.
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Analysis
by VulDB Data Team • 12/08/2024
The vulnerability described in CVE-2004-0158 represents a critical buffer overflow flaw within the lbreakout2 game application that enables local privilege escalation through manipulation of the HOME environment variable. This issue affects multiple source code files including editor.c, theme.c, manager.c, config.c, game.c, levels.c, and main.c, indicating a systemic weakness in the application's input validation mechanisms. The buffer overflow occurs when the application processes an excessively long HOME environment variable, causing memory corruption that can be exploited to elevate privileges to the games group level. The vulnerability's exploitation potential stems from the application's failure to properly validate the length of environment variables before processing them, creating an opportunity for attackers to overwrite adjacent memory regions and potentially execute arbitrary code with elevated privileges.
The technical nature of this vulnerability aligns with CWE-121, which describes buffer overflow conditions where insufficient bounds checking allows attackers to write past the end of allocated buffer space. This particular flaw manifests in the context of environment variable handling, where the lbreakout2 application does not implement proper input sanitization for the HOME variable before using it to construct or process data structures. The attack vector is specifically local since the vulnerability requires the attacker to be able to set environment variables, which is typically possible for any user on the system. The exploitation process involves crafting a sufficiently long HOME environment variable that exceeds the allocated buffer space in any of the seven affected source files, leading to memory corruption that can be leveraged for privilege escalation.
The operational impact of this vulnerability extends beyond simple privilege escalation to potentially compromise the entire gaming environment and system integrity. When local users can gain games group privileges through this buffer overflow, they effectively acquire access to resources and capabilities typically restricted to the games group, including potential access to game configuration files, high score databases, and other gaming-related system resources. This escalation of privileges can enable attackers to modify game settings, manipulate high score tables, or potentially gain access to other system resources that are normally protected from regular user accounts. The multi-file nature of the vulnerability suggests that the buffer overflow is likely occurring in a common utility function or shared memory handling routine that is called from multiple points within the application, making the exploitation more reliable and widespread.
Mitigation strategies for this vulnerability should focus on implementing proper bounds checking and input validation throughout the application's codebase, particularly in the handling of environment variables. The most effective remediation involves modifying the affected source files to implement proper buffer size validation before processing the HOME environment variable, ensuring that input data does not exceed allocated buffer boundaries. System administrators should also consider implementing environment variable restrictions and monitoring for unusual HOME variable lengths in system logs. Additionally, the application should be updated to use safer string handling functions that automatically perform bounds checking, such as those provided in the C11 standard's string handling library. The vulnerability's classification under ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation', highlights the need for comprehensive system hardening measures including regular security updates, privilege separation, and monitoring for abnormal privilege escalation attempts. The fix should also include implementing stack canaries or other memory protection mechanisms to detect and prevent buffer overflow exploitation attempts.