CVE-2011-4116 in File::Temp
Summary
by MITRE
_is_safe in the File::Temp module for Perl does not properly handle symlinks.
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Analysis
by VulDB Data Team • 08/04/2025
The vulnerability identified as CVE-2011-4116 resides within the File::Temp Perl module, a widely used component for creating temporary files and directories in Perl applications. This module serves as a critical utility for developers who need to generate temporary storage locations during program execution, particularly in environments where security and proper resource management are paramount. The flaw specifically affects the _is_safe function which is responsible for validating the safety of temporary file paths and ensuring that these locations cannot be exploited through malicious symlink manipulation.
The technical implementation of the vulnerability stems from inadequate handling of symbolic links within the path validation logic of the File::Temp module. When applications use this module to create temporary files, the _is_safe function should verify that the intended temporary location is secure and cannot be manipulated by attackers through symlink attacks. However, the flawed implementation fails to properly resolve or validate symbolic links, allowing potential attackers to create malicious symlinks that point to sensitive system files or directories. This oversight enables attackers to bypass intended security checks and potentially write data to unauthorized locations, or in some cases, read sensitive information from protected areas of the filesystem.
The operational impact of this vulnerability extends across numerous Perl-based applications and systems that rely on the File::Temp module for temporary file management. Attackers exploiting this weakness could manipulate temporary file creation processes to redirect output to arbitrary locations, potentially leading to privilege escalation, data corruption, or information disclosure. The vulnerability is particularly dangerous in web applications or system utilities where temporary files are created with elevated privileges, as it could allow unauthenticated attackers to inject malicious content into system directories or overwrite critical files. This weakness aligns with CWE-377, which addresses the creation of temporary files with insecure permissions, and represents a classic example of insecure temporary file handling that can be leveraged for privilege escalation attacks.
Mitigation strategies for CVE-2011-4116 require immediate updates to the File::Temp module to proper implement symlink resolution and validation within the _is_safe function. System administrators should ensure that all affected Perl applications are updated to use a patched version of the module, with particular attention to applications running with elevated privileges or handling sensitive data. Security monitoring should include checks for unusual temporary file creation patterns and potential symlink manipulation attempts. The vulnerability demonstrates the importance of proper file system access control and the necessity of robust path validation in security-critical software components, aligning with ATT&CK technique T1059.007 for execution through scripting and T1078.004 for valid accounts with elevated privileges. Organizations should also implement comprehensive patch management processes to address similar vulnerabilities in other language-specific temporary file handling libraries, as this represents a common pattern of insecure temporary file management across different programming environments.