CVE-2014-2277 in perltidy
Summary
by MITRE
The make_temporary_filename function in perltidy 20120701-1 and earlier allows local users to obtain sensitive information or write to arbitrary files via a symlink attack, related to use of the tmpnam function.
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Analysis
by VulDB Data Team • 01/17/2021
The vulnerability identified as CVE-2014-2277 affects the perltidy utility version 20120701-1 and earlier, presenting a critical security flaw in how temporary file names are generated during the program execution. This issue stems from the improper implementation of the make_temporary_filename function which relies on the tmpnam system call, creating a predictable and exploitable condition that enables local attackers to manipulate file operations. The flaw directly relates to the insecure handling of temporary files, where the system generates predictable temporary file names that can be anticipated and targeted by malicious actors.
The technical implementation of this vulnerability exploits the inherent weaknesses in the tmpnam function which is known to generate temporary file names that are predictable and susceptible to race conditions. When perltidy creates temporary files using this function, it does not adequately secure the temporary file creation process, leaving the system vulnerable to symlink-based attacks. An attacker can create symbolic links in the expected temporary file locations before the application attempts to create its temporary file, causing the application to write data to unintended locations or read sensitive information from privileged files. This represents a classic case of insecure temporary file handling where the application's reliance on predictable naming conventions creates an attack surface that can be easily exploited.
The operational impact of this vulnerability extends beyond simple information disclosure to include arbitrary file write capabilities, making it particularly dangerous for local attackers who can leverage this weakness to escalate privileges or compromise system integrity. When exploited, the vulnerability allows attackers to write data to any location on the filesystem that the application process has write permissions for, potentially enabling privilege escalation attacks or the injection of malicious code into system files. The vulnerability is particularly concerning because it operates at the local user level, meaning that any user with access to the system can potentially exploit it without requiring special privileges or network access.
Security mitigations for CVE-2014-2277 should focus on replacing the vulnerable tmpnam function with secure alternatives such as mkstemp or mkdtemp which generate unique temporary file names and open them atomically to prevent race conditions. The fix requires updating the make_temporary_filename function to use proper secure temporary file creation methods that prevent symlink attacks and ensure that temporary files are created with appropriate permissions and in secure locations. Organizations should also implement proper access controls and file system permissions to limit the impact of any potential exploitation, while system administrators should ensure that all instances of perltidy are updated to versions that address this vulnerability. This vulnerability aligns with CWE-377 and CWE-378, which address insecure temporary file creation and weak temporary file handling respectively, and maps to ATT&CK technique T1059.007 for execution through command-line interfaces, demonstrating the broader implications of insecure file handling in system security.
The root cause of this vulnerability demonstrates poor security practices in temporary file management and highlights the importance of following secure coding guidelines for file system operations. The use of deprecated functions like tmpnam without proper security considerations creates dangerous attack vectors that can be easily exploited by local attackers. This vulnerability serves as a reminder of the critical importance of proper temporary file handling in software development, particularly in utilities that process user data and operate with elevated privileges. The attack surface created by predictable temporary file names and the lack of proper file access controls makes this vulnerability particularly dangerous in environments where multiple users share the same system resources, as it can be exploited to gain unauthorized access to system files or escalate privileges to higher user accounts.