CVE-2004-1689 in sudo
Summary
by MITRE
sudoedit (aka sudo -e) in sudo 1.6.8 opens a temporary file with root privileges, which allows local users to read arbitrary files via a symlink attack on the temporary file before quitting sudoedit.
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Analysis
by VulDB Data Team • 12/16/2024
The vulnerability identified as CVE-2004-1689 represents a critical privilege escalation flaw within the sudo command execution framework, specifically affecting sudo version 1.6.8 and earlier. This issue manifests through the sudoedit utility, which is designed to provide users with the ability to edit files with elevated privileges while maintaining security boundaries. The vulnerability stems from improper handling of temporary files during the file editing process, creating a window of opportunity for malicious local users to exploit the system's privilege model.
The technical flaw occurs when sudoedit creates a temporary file with root privileges during the file editing operation. This temporary file is created in a location where local users can establish symbolic links that point to arbitrary files on the system. When the user exits sudoedit, the temporary file is processed in a manner that allows the symbolic link to be followed, thereby enabling the local user to read files that they would normally not have access to. This represents a classic race condition vulnerability where the security check occurs before the actual file operations are completed. The vulnerability is categorized under CWE-377 as "Insecure Temporary File" and also relates to CWE-284 as "Improper Access Control" since the temporary file creation does not properly restrict access permissions.
The operational impact of this vulnerability is significant as it allows local users to bypass normal file access controls and read sensitive files that are protected by root ownership or restrictive permissions. Attackers can leverage this to access configuration files, password databases, system logs, or other sensitive information that should only be accessible to privileged users. The attack vector is particularly concerning because it requires minimal privileges to execute and can be automated to systematically enumerate and extract valuable information from the target system. This vulnerability directly maps to ATT&CK technique T1003.008 "OS Credential Dumping: Smart Card" and T1059.001 "Command and Scripting Interpreter: PowerShell" in the context of privilege escalation and information gathering operations.
Mitigation strategies for CVE-2004-1689 involve immediate patching of the sudo package to versions that properly handle temporary file creation with appropriate permissions and atomic operations. System administrators should ensure that all sudo installations are updated to versions that address this vulnerability, as the fix typically involves creating temporary files with restrictive permissions or using atomic file operations that prevent symbolic link attacks. Additional defensive measures include implementing proper file system permissions, monitoring for suspicious temporary file creation patterns, and employing privilege separation techniques that minimize the exposure of root privileges during file operations. Organizations should also consider implementing file integrity monitoring solutions to detect and alert on unauthorized symbolic link creation in directories where temporary files are handled. The vulnerability demonstrates the importance of proper temporary file handling in security-critical applications and the necessity of following secure coding practices that prevent race conditions and privilege escalation vectors.