CVE-2004-0157 in xonix
Summary
by MITRE
x11.c in xonix 1.4 and earlier uses the current working directory to find and execute the rmail program, which allows local users to execute arbitrary code by modifying the path to point to a malicious rmail program.
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Analysis
by VulDB Data Team • 06/29/2021
The vulnerability described in CVE-2004-0157 represents a classic path traversal and privilege escalation flaw affecting the xonix game version 1.4 and earlier. This issue stems from improper handling of system command execution within the x11.c source file, where the application relies on the current working directory to locate and execute the rmail program. The flaw creates a dangerous dependency on the execution environment's PATH variable and working directory state, allowing malicious actors to manipulate the program flow through directory traversal techniques.
The technical implementation of this vulnerability involves the application's use of a hardcoded or improperly constructed command execution path that does not explicitly specify the full path to the rmail utility. When xonix executes system commands to handle mail functionality, it relies on the system's default PATH resolution mechanism rather than absolute paths. This design flaw enables attackers to place a malicious rmail program in a directory that appears earlier in the PATH, causing the legitimate xonix application to execute the attacker-controlled binary instead of the intended system utility. The vulnerability operates under CWE-78 principle of improper neutralization of special elements used in OS commands, specifically manifesting as command injection through path manipulation.
The operational impact of this vulnerability is significant for local users who can exploit it to execute arbitrary code with the privileges of the xonix process. Since the application typically runs with user permissions, successful exploitation allows attackers to gain unauthorized code execution capabilities within the user's session context. This represents a privilege escalation vector that could potentially be leveraged to establish persistent access or escalate privileges further if the xonix process runs with elevated permissions. The attack requires local system access and knowledge of the application's behavior, making it a local privilege escalation vulnerability rather than a remote exploit.
Mitigation strategies for CVE-2004-0157 should focus on implementing proper input validation and command execution practices that align with security best practices and industry standards. The most effective fix involves modifying the x11.c source code to use absolute paths when executing system commands, specifically the rmail program, rather than relying on PATH resolution. This approach directly addresses the underlying CWE-78 issue by eliminating the command injection vector through path manipulation. Additionally, implementing proper privilege separation and ensuring that applications do not execute commands with elevated privileges when unnecessary helps reduce the potential impact of such vulnerabilities. Security practitioners should also consider implementing access controls and monitoring for unauthorized modifications to system directories, as this vulnerability could be exploited through various attack vectors including social engineering or compromised system accounts. The remediation approach should follow ATT&CK technique T1059.001 for command and scripting interpreter, specifically targeting the execution of malicious code through improper command handling.
The vulnerability demonstrates the importance of secure coding practices and proper command execution handling in application development. Legacy applications like xonix often contain such flaws due to historical coding practices that did not account for modern security requirements. This particular vulnerability highlights the need for comprehensive security reviews of existing software systems, particularly those that interact with system utilities or execute external commands. Organizations should implement regular security assessments and code reviews to identify similar path traversal and command injection vulnerabilities that may exist in other applications within their infrastructure. The fix for CVE-2004-0157 represents a fundamental security improvement that aligns with defense-in-depth principles and helps protect against similar classes of vulnerabilities that could be exploited in more sophisticated attack scenarios.