CVE-2014-1875 in Capture-tiny
Summary
by MITRE
The Capture::Tiny module before 0.24 for Perl 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 • 12/20/2024
The Capture::Tiny module for perl versions prior to 024 contains a critical security vulnerability that enables local attackers to write to arbitrary files through a carefully crafted symbolic link attack against temporary files. This flaw represents a classic race condition vulnerability where the module creates temporary files without proper security controls, making it susceptible to exploitation by malicious users who can manipulate the file system during the temporary file creation process. The vulnerability specifically affects systems where perl applications rely on Capture::Tiny for capturing output from subprocesses, creating a potential attack vector that could be leveraged for privilege escalation or data manipulation.
The technical implementation of this vulnerability stems from improper handling of temporary file creation within the Capture::Tiny module. When the module executes commands and attempts to capture their output, it generates temporary files in a predictable location without adequate permissions or atomic creation mechanisms. An attacker can exploit this by creating a symbolic link with the same name as the temporary file that the module will create, pointing to a sensitive target file. When the module attempts to write to what it believes is a temporary file, it actually writes to the file pointed to by the symbolic link, thereby enabling arbitrary file write operations. This pattern aligns with common software security flaws categorized under CWE-377 and CWE-378, which address insecure temporary file handling and improper file permissions respectively.
The operational impact of this vulnerability extends beyond simple file system manipulation to potentially enable more serious security breaches. Local attackers with minimal privileges can exploit this flaw to overwrite configuration files, log files, or other sensitive system resources that might be owned by privileged processes. The attack becomes particularly dangerous when applications using Capture::Tiny run with elevated privileges, as the arbitrary file write capability could be used to inject malicious content into system files or binaries. This vulnerability also demonstrates the broader risk of insecure temporary file handling in scripting languages and highlights the importance of proper file system security controls in application development. The flaw can be exploited through various attack vectors including privilege escalation scenarios where an attacker can manipulate the temporary file creation process to write to files that should normally be protected.
Security mitigations for this vulnerability require immediate patching of the Capture::Tiny module to version 0.24 or later, where the developers have implemented proper temporary file handling mechanisms including atomic creation and appropriate permission settings. System administrators should also implement additional controls such as restricting write permissions in temporary directories and monitoring for suspicious symbolic link creation patterns. The vulnerability serves as a reminder of the critical importance of proper file system security in perl applications and aligns with ATT&CK technique T1059.007 for executing malicious code through scripting languages. Organizations should conduct thorough vulnerability assessments to identify other perl modules that might be susceptible to similar temporary file handling flaws, and implement security awareness training for developers regarding secure coding practices for temporary file management. Regular security audits of perl applications and their dependencies should include checks for insecure temporary file handling patterns to prevent similar vulnerabilities from being introduced in future code deployments.