CVE-2002-1377 in VIM
Summary
by MITRE
vim 6.0 and 6.1, and possibly other versions, allows attackers to execute arbitrary commands using the libcall feature in modelines, which are not sandboxed but may be executed when vim is used to edit a malicious file, as demonstrated using mutt.
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Analysis
by VulDB Data Team • 07/19/2019
The vulnerability identified as CVE-2002-1377 represents a critical security flaw in vim text editor versions 6.0 and 6.1, with potential impacts extending to other versions within the same release cycle. This vulnerability specifically targets the libcall feature within vim's modeline functionality, creating an attack vector that allows remote code execution through seemingly benign file editing operations. The flaw exploits the lack of proper sandboxing mechanisms that should normally isolate potentially dangerous operations within the editor environment.
The technical implementation of this vulnerability leverages vim's modeline processing capabilities, which are designed to allow users to set editor options automatically based on file content. When vim encounters a modeline in a file, it typically processes these settings in a restricted environment to prevent malicious code execution. However, the libcall feature within modelines bypasses these security restrictions, enabling attackers to invoke system functions directly through the editor. This occurs when vim processes a malicious file containing specially crafted modelines that reference external libraries or system commands, effectively allowing arbitrary command execution with the privileges of the user running vim.
The operational impact of this vulnerability extends beyond simple file editing scenarios, as demonstrated through attacks targeting mutt email client. Attackers can craft malicious email messages or configuration files that, when opened in vim, trigger the execution of arbitrary commands on the victim's system. This creates a significant risk for users who frequently edit configuration files or process untrusted text content, particularly in environments where vim serves as a primary text editing tool. The vulnerability is particularly dangerous because it can be exploited through legitimate file editing workflows without requiring special privileges or complex attack chains.
This vulnerability maps directly to CWE-78, which describes improper neutralization of special elements used in OS commands, and aligns with ATT&CK technique T1059.001 for command and script injection. The lack of sandboxing in vim's modeline processing creates an environment where attackers can escalate privileges through command execution, potentially leading to complete system compromise. Organizations using vim in production environments face significant risk if proper mitigation measures are not implemented, as the vulnerability can be exploited through simple file access operations that occur during normal user workflows. The attack surface is particularly broad given vim's widespread adoption across Unix-like systems and its common usage in development environments where users frequently edit configuration files and system scripts.
Mitigation strategies for CVE-2002-1377 include immediate patching of vim installations to versions that properly sandbox modeline processing and disable potentially dangerous libcall features. System administrators should implement strict file access controls and consider disabling vim modeline processing entirely for sensitive environments. Additionally, users should be trained to avoid opening untrusted files in vim and to verify file contents before editing. Network-level protections such as email filtering and file scanning can help prevent malicious files from reaching users in the first place. Regular security audits should verify that vim installations are properly configured to prevent modeline-based command execution and that system-wide security policies prevent exploitation of this class of vulnerability through proper access control and privilege management.