CVE-2000-0715 in DiskCheck
Summary
by MITRE
DiskCheck script diskcheck.pl in Red Hat Linux 6.2 allows local users to create or overwrite arbitrary files via a symlink attack on a temporary file.
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Analysis
by VulDB Data Team • 05/27/2018
The vulnerability described in CVE-2000-0715 represents a classic symlink attack scenario that exploited weak temporary file handling in the DiskCheck script distributed with Red Hat Linux 6.2. This issue falls under the category of insecure temporary file creation vulnerabilities, which are systematically catalogued under CWE-377 as insecure temporary file creation practices. The vulnerability specifically targeted the diskcheck.pl script that was part of the Red Hat Linux 6.2 distribution, making it a significant concern for systems running this particular version of the operating system.
The technical flaw in this vulnerability stems from the script's improper handling of temporary files during execution. When the DiskCheck script ran, it created temporary files without proper security checks, allowing local users to manipulate the system by creating symbolic links in the expected temporary file locations. This attack vector enabled malicious users to place malicious content at predetermined locations where the script would later write data, effectively allowing arbitrary file creation or overwriting with elevated privileges. The attack leveraged the principle of time-of-check to time-of-use vulnerabilities, where the script checked for file existence before performing operations, but the file state could be altered between these checks.
The operational impact of this vulnerability was substantial for systems running Red Hat Linux 6.2, as it provided local attackers with a method to escalate privileges or compromise system integrity. The ability to create or overwrite arbitrary files meant that attackers could potentially modify critical system files, configuration data, or even executable programs, leading to unauthorized system access or complete compromise. This vulnerability particularly affected systems where the DiskCheck script was executed with elevated privileges, as it could be exploited to gain higher-level access to system resources. The attack required local access but could result in significant security breaches, making it a serious concern for system administrators managing these older distributions.
Mitigation strategies for this vulnerability focused on immediate patching of the affected Red Hat Linux 6.2 systems with updated versions of the DiskCheck script that properly handled temporary file creation. The recommended approach involved implementing secure temporary file creation practices, such as using unique filenames with random components, setting appropriate file permissions, and employing atomic file creation methods. Organizations should have also considered implementing access controls to limit local user privileges and monitoring for unauthorized file modifications. This vulnerability highlighted the importance of proper file handling security practices and the need for regular security updates. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and could be classified under initial access and execution tactics, as local users could leverage this weakness to gain elevated system access. The incident underscored the critical need for secure coding practices and regular vulnerability assessments to prevent similar issues in system administration scripts and utilities.