CVE-2005-0069 in VIM
Summary
by MITRE
The (1) tcltags or (2) vimspell.sh scripts in vim 6.3 allow local users to overwrite or create arbitrary files via a symlink attack on temporary files.
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Analysis
by VulDB Data Team • 06/18/2019
The vulnerability identified as CVE-2005-0069 affects the tcltags and vimspell.sh scripts distributed with vim version 6.3, representing a classic symlink attack scenario that exploits insecure temporary file handling practices. This vulnerability falls under the category of insecure temporary file creation as classified by CWE-377, where the scripts fail to properly validate or secure temporary file operations, creating opportunities for malicious users to manipulate file system permissions and execute unauthorized file operations. The issue stems from the scripts' improper handling of temporary file names and their lack of proper atomic file creation mechanisms, which allows attackers to establish symbolic links in strategic locations before the scripts attempt to create temporary files.
The technical flaw manifests when these scripts execute in environments where local users have write permissions to directories where temporary files are created. During normal operation, the scripts generate temporary files in predictable locations without implementing proper security measures such as creating temporary files with unique names, using secure file creation modes, or performing proper permission checks. Attackers can exploit this by creating symbolic links with the same names as expected temporary files in directories where the scripts operate, causing the scripts to write data to attacker-controlled locations instead of intended destinations. This type of attack directly relates to the ATT&CK technique T1556.001 for credential access through the exploitation of insecure file permissions and symbolic link manipulation.
The operational impact of this vulnerability extends beyond simple file overwrites, as it can enable local privilege escalation or arbitrary code execution depending on the context where the scripts are executed. When these scripts run with elevated privileges, such as system-wide installations or in setuid contexts, attackers can leverage this weakness to place malicious content in critical system locations, potentially compromising the entire system. The vulnerability affects both tcltags, which is used for generating tag files for tcl source code, and vimspell.sh, which handles spell checking operations, making it particularly dangerous as these tools are commonly used in development environments and system administration tasks. The attack vector requires local access and basic file system manipulation capabilities, making it relatively easy to exploit in environments where users have write permissions to temporary directories.
Mitigation strategies for CVE-2005-0069 should focus on implementing secure temporary file creation practices that align with industry standards and security best practices. Organizations should ensure that all scripts properly validate temporary file creation by using secure file creation functions that prevent race conditions, such as creating files with exclusive access modes or using secure temporary directory mechanisms. The recommended approach includes implementing proper directory permissions, using unique temporary file names, and avoiding predictable naming schemes that attackers can exploit. System administrators should also consider updating to newer versions of vim where these issues have been addressed, as the vulnerability represents a known weakness in the software's security implementation that has been corrected in subsequent releases. Additionally, implementing proper file system monitoring and access controls can help detect and prevent unauthorized symbolic link creation in critical directories where these scripts operate.