CVE-2005-0503 in uim
Summary
by MITRE
uim before 0.4.5.1 trusts certain environment variables when libuim is used in setuid or setgid applications which allows local users to gain privileges.
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Analysis
by VulDB Data Team • 06/05/2019
The vulnerability described in CVE-2005-0503 affects the uim input method framework version 0.4.5.1 and earlier, presenting a critical privilege escalation risk when the framework is employed in setuid or setgid applications. This issue stems from the improper handling of environment variables within the uim library, creating a security flaw that local attackers can exploit to elevate their privileges. The vulnerability specifically targets applications that utilize the uim library and operate with elevated privileges, making it particularly dangerous in systems where input method frameworks are integrated into security-sensitive applications.
The technical flaw manifests when the uim library processes environment variables without adequate validation or sanitization, particularly in contexts where the application runs with elevated privileges. When a setuid or setgid application incorporates libuim, the library may inadvertently trust and utilize environment variables that an attacker could manipulate. This behavior violates fundamental security principles by allowing unprivileged users to influence the execution environment of privileged processes. The vulnerability is classified under CWE-276, which deals with incorrect permissions for critical resources, and represents a classic case of insecure environment variable handling that enables privilege escalation attacks.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it can be leveraged to compromise entire systems when uim is integrated into critical applications. Attackers can manipulate environment variables such as PATH, LD_LIBRARY_PATH, or other library loading variables to inject malicious code or libraries into the privileged execution context. This allows them to execute arbitrary code with the elevated privileges of the target application, potentially leading to complete system compromise. The vulnerability affects any application that uses libuim in setuid or setgid mode, including text editors, window managers, or other desktop applications that may be configured to run with elevated privileges.
Mitigation strategies for CVE-2005-0503 focus on several key approaches that align with established security best practices and ATT&CK framework recommendations for privilege escalation prevention. The most effective immediate solution involves upgrading to uim version 0.4.5.1 or later, where the problematic environment variable handling has been corrected. System administrators should also implement proper environment variable sanitization within applications that use libuim, ensuring that critical environment variables are either cleared or validated before invoking library functions. Additional protective measures include restricting the use of setuid/setgid applications, implementing proper access controls, and monitoring for suspicious environment variable modifications. The vulnerability demonstrates the importance of the principle of least privilege and highlights the necessity of careful environment variable handling in security-sensitive code, particularly when dealing with libraries that may be used in elevated privilege contexts. Organizations should also consider implementing runtime protection mechanisms that monitor for unauthorized environment variable modifications in setuid/setgid processes, as recommended by various security frameworks including NIST SP 800-53 and ISO 27001 standards.