CVE-2014-1858 in Numpy
Summary
by MITRE
__init__.py in f2py in NumPy before 1.8.1 allows local users to write to arbitrary files via a symlink attack on a temporary file.
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Analysis
by VulDB Data Team • 01/20/2023
The vulnerability described in CVE-2014-1858 resides within the f2py component of NumPy, a fundamental library for scientific computing in Python that facilitates interaction between Python and Fortran code. This flaw specifically affects versions of NumPy prior to 1.8.1 and represents a classic symlink attack scenario that exploits insecure temporary file handling practices. The vulnerability occurs during the initialization process of f2py's _init_.py file, where the system creates temporary files without proper security checks, making it susceptible to manipulation by local attackers who can leverage symbolic links to redirect file operations to arbitrary locations on the filesystem.
The technical implementation of this vulnerability stems from the improper handling of temporary files during the f2py execution process. When NumPy processes Fortran code through f2py, it generates temporary files to store intermediate compilation results and configuration data. The flaw manifests when these temporary files are created using predictable naming conventions without adequate checks to prevent symlink attacks. An attacker with local access can create symbolic links with the same names as the expected temporary files, effectively intercepting the file operations and causing the system to write data to locations of the attacker's choosing rather than the intended temporary directories.
From an operational impact perspective, this vulnerability presents a significant security risk for systems running vulnerable versions of NumPy, particularly in environments where multiple users share the same system or where untrusted code might be executed. The attack vector allows for arbitrary file write operations, which could potentially lead to privilege escalation, data corruption, or even system compromise depending on the target file locations and the privileges of the affected process. The vulnerability is classified under CWE-377 as "Insecure Temporary File" and aligns with ATT&CK technique T1059.001 for executing code through interpreted languages, as it enables attackers to manipulate the Python execution environment through file system manipulation.
The exploitation of this vulnerability requires local system access and knowledge of the specific temporary file naming conventions used by f2py. Attackers typically create symbolic links in directories where the temporary files are expected to be created, then trigger the vulnerable f2py process to write data to these links, effectively writing to arbitrary locations on the filesystem. This type of attack is particularly concerning in shared computing environments, containerized deployments, or systems where automated processes might execute f2py operations with elevated privileges. The remediation approach involves upgrading to NumPy version 1.8.1 or later, where the temporary file handling has been improved to use secure creation methods that prevent symlink attacks.
Security practitioners should consider this vulnerability as part of broader system hardening efforts, particularly in environments where scientific computing libraries are extensively used. The vulnerability demonstrates the importance of proper temporary file handling practices and the potential consequences of inadequate security controls in widely-used open source libraries. Organizations should implement automated patch management processes to ensure timely updates to critical components like NumPy, and conduct regular security assessments to identify similar vulnerabilities in other system components. The fix implemented in NumPy 1.8.1 addresses the root cause by ensuring that temporary files are created with proper permissions and atomic operations that prevent symlink-based attacks, aligning with industry best practices for secure temporary file management as recommended in various security frameworks and guidelines.