CVE-2005-1751 in shtool
Summary
by MITRE
Race condition in shtool 2.0.1 and earlier allows local users to create or modify arbitrary files via a symlink attack on the .shtool.$$ temporary file, a different vulnerability than CVE-2005-1759.
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Analysis
by VulDB Data Team • 06/02/2019
The vulnerability identified as CVE-2005-1751 represents a critical race condition flaw in shtool version 2.0.1 and earlier, which enables local attackers to manipulate the file system through symbolic link attacks. This issue specifically targets the temporary file .shtool.$$ that shtool creates during its operation, making it susceptible to exploitation by malicious users who can manipulate the file system during the window of vulnerability. The race condition occurs when the program creates a temporary file without proper atomic operations, allowing an attacker to establish a symbolic link with the same name before the legitimate file creation process completes. This vulnerability operates under the broader category of insecure temporary file handling, which is classified under CWE-377 and CWE-378, both of which address the improper creation and handling of temporary files in software applications. The attack vector specifically aligns with the ATT&CK technique T1059.007, which involves the use of scripting to execute malicious code through system utilities.
The technical implementation of this vulnerability involves shtool's failure to properly secure temporary file creation processes, particularly when dealing with the .shtool.$$ naming convention. During normal operation, shtool generates this temporary file to store intermediate results or configuration data, but due to the race condition, an attacker can intercept this process by creating a symbolic link with the same name in the target directory. The window of opportunity for exploitation is extremely narrow but sufficient for a determined attacker to successfully replace the legitimate temporary file with a malicious symlink pointing to any location on the file system. This allows the attacker to potentially create or modify arbitrary files with the privileges of the user running shtool, which could include system-critical files or configuration data. The vulnerability demonstrates poor security practices in file system manipulation and highlights the importance of atomic file operations in preventing such attacks.
The operational impact of CVE-2005-1751 extends beyond simple file manipulation as it can enable more sophisticated attacks when combined with other exploitation techniques. An attacker who successfully exploits this vulnerability can potentially escalate privileges if shtool is executed with elevated permissions, or they can corrupt system files to cause denial of service or create persistent backdoors. The attack is particularly concerning because it does not require network access or complex exploitation techniques, making it accessible to any local user with basic system access. The vulnerability also demonstrates the broader problem of legacy software maintenance, as shtool 2.0.1 and earlier versions were widely distributed and used in various system administration contexts, making the potential attack surface extensive. Organizations using affected versions of shtool should consider this vulnerability as part of their overall security posture, particularly in environments where local privilege escalation is a concern. The issue also relates to the broader category of privilege escalation through file system manipulation, which is addressed in various security frameworks including the NIST Cybersecurity Framework and ISO 27001 standards for information security management. Remediation efforts should focus on updating to patched versions of shtool, implementing proper temporary file handling procedures, and conducting security audits of system utilities that may be susceptible to similar race condition vulnerabilities.