CWE-427 Uncontrolled Search Path Element Vulnerability Analysis and Mitigation

CWE-427: Uncontrolled Search Path Element Vulnerability Overview This vulnerability refers to products that use fixed or controlled search paths to locate resources, but one or more locations within the path may be controlled by unintended actors. Attackers can inject malicious code by modifying environment variables (e.g., ), exploiting the current working directory, or relying on incompletely qualified paths (e.g., using only the filename instead of the full path). Common Scenarios: Windows systems: When calling or to load a DLL, if a fully qualified path is not provided, the system will search locations such as the current working directory. Linux/Unix systems: A path containing an empty element (e.g., ) is interpreted as the current working directory. Package management: During dependency resolution, public repositories may be searched before private ones (dependency confusion). Impact Scope Execution of unauthorized code or commands: Attackers may execute malicious programs with elevated privileges. Compromise of confidentiality, integrity, and availability: May lead to data leakage, system tampering, or service disruption. Remediation Measures 1. Hardcode secure paths: Restrict the search path to known safe values (e.g., system directories), or allow only administrators to specify them in configuration files. 2. Use fully qualified paths: When invoking programs in code, use complete absolute paths instead of relying on environment variables or the current directory. 3. Remove or restrict environment variables: Remove or restrict environment variables such as , before calling external programs. 4. Check and sanitize paths: Verify the search path before execution and remove unsafe elements such as the current working directory. 5. Use explicit path functions: Use functions that require a full path (e.g., ) and avoid those that rely on (e.g., ). POC Code Examples Example 1: Java (NIS update) Description: The absolute path of is not specified; attackers can modify to point to a malicious program. Example 2: Go (LookPath function) Description: searches directories in . Attackers can create a malicious file with the same name (e.g., ) and place it in , causing malicious code execution. Example 3: Dependency Confusion (Python/Node.js/Ruby) Description: Attackers publish malicious packages with the same names as private repository packages in public repositories, exploiting dependency resolution order (public first) to induce the system to download and execute malicious code. Related CVE Examples CVE-2023-25815: Hardcoded path leads to exploitation of the function. CVE-2022-4826: Go executes malicious based on search. CVE-2020-26284: Go static site generator searches current directory on Windows to execute malicious code. CVE-2019-1552: SSL package searches config directory, allowing local attacker to create malicious config files. CVE-2010-3402: "DLL hijacking" issue in document editor. CVE-1999-1461: Product trusts environment variable, allowing local users to gain root privileges by modifying .

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CWE-427 Uncontrolled Search Path Element Vulnerability Analysis and Mitigation