CVE-2005-3149 in uim
Summary
by MITRE
uim 0.4.x before 0.4.9.1 and 0.5.0 and earlier does not properly handle the libuim_vanilla environment variable when a suid or sgid application is linked to libuim such as immodule for qt which allows local users to gain privileges.
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Analysis
by VulDB Data Team • 08/04/2019
The vulnerability described in CVE-2005-3149 represents a critical privilege escalation issue within the uim input method framework version 0.4.x prior to 0.4.9.1 and 0.5.0 and earlier. This flaw specifically targets the improper handling of the libuim_vanilla environment variable within setuid or setgid applications that utilize libuim libraries. The uim framework serves as a universal input method system that supports various input methods including Chinese, Japanese, and Korean text input, making it a critical component in internationalization support for desktop applications.
The technical root cause of this vulnerability stems from insufficient sanitization of environment variables within the libuim library implementation. When applications with elevated privileges such as immodule for qt are linked against libuim and subsequently executed with setuid or setgid permissions, the libuim_vanilla environment variable can be manipulated by local users to inject malicious code or alter the library's behavior. This occurs because the library does not properly validate or sanitize the environment variable before processing it, allowing attackers to influence the execution flow of privileged code. The vulnerability is particularly dangerous because it leverages the inherent trust placed in setuid applications, which are designed to run with elevated privileges to perform system-level operations.
The operational impact of this vulnerability is severe as it enables local users to potentially escalate their privileges from standard user level to that of the privileged application owner. This privilege escalation can lead to unauthorized system access, data manipulation, or further exploitation within the compromised system. Attackers can exploit this vulnerability by setting the libuim_vanilla environment variable to point to malicious libraries or execute arbitrary code within the context of the privileged application. The vulnerability affects not only the immediate application but potentially the entire system if the setuid application has broad system access capabilities. This type of vulnerability directly maps to CWE-276, which describes inadequate privileges for setuid or setgid programs, and aligns with ATT&CK technique T1548.001 for privilege escalation through setuid/setgid binaries.
Mitigation strategies for this vulnerability include updating to uim version 0.4.9.1 or later, which contains the necessary patches to properly sanitize environment variables. System administrators should also implement proper environment variable validation and sanitization within applications that utilize setuid or setgid permissions. Additionally, the principle of least privilege should be enforced by minimizing the number of setuid/setgid applications on the system and ensuring that only essential applications require elevated privileges. Security monitoring should be implemented to detect unusual environment variable modifications, and regular security audits should be conducted to identify potentially vulnerable applications within the system infrastructure.