CVE-2012-4463 in Midnight Commander
Summary
by MITRE
Midnight Commander (mc) 4.8.5 does not properly handle the (1) MC_EXT_SELECTED or (2) MC_EXT_ONLYTAGGED environment variables when multiple files are selected, which allows user-assisted remote attackers to execute arbitrary commands via a crafted file name.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 12/19/2021
The vulnerability identified as CVE-2012-4463 affects Midnight Commander version 4.8.5, a widely used file manager for Unix-like systems that provides a visual interface for file operations. This flaw resides in how the application processes specific environment variables during file selection operations, creating a command injection vector that can be exploited by remote attackers. The vulnerability specifically impacts the handling of MC_EXT_SELECTED and MC_EXT_ONLYTAGGED environment variables when multiple files are selected within the file manager interface.
The technical flaw stems from inadequate input validation and sanitization within the command execution pipeline of Midnight Commander. When users select multiple files and the application processes these selections, it fails to properly escape or validate special characters in filenames that may contain shell metacharacters. The MC_EXT_SELECTED and MC_EXT_ONLYTAGGED environment variables are designed to extend functionality by allowing external commands to be executed based on file selection criteria, but the implementation does not sufficiently sanitize the input data before incorporating it into shell commands. This oversight creates a classic command injection vulnerability where attacker-controlled data can be interpreted as shell commands rather than simple file names.
The operational impact of this vulnerability is significant as it allows user-assisted remote attackers to execute arbitrary commands on systems running affected versions of Midnight Commander. An attacker would need to convince a victim to select a specially crafted filename that contains malicious shell commands, which could then be executed with the privileges of the user running mc. This could potentially lead to complete system compromise, data exfiltration, or further network reconnaissance. The vulnerability is particularly dangerous in multi-user environments where different users may be running Midnight Commander with varying privilege levels. The attack requires social engineering to get a victim to select a malicious file, but once executed, the consequences can be severe.
Mitigation strategies should focus on immediate patching of the affected software to the latest stable version that contains the necessary fixes for proper environment variable handling. System administrators should also implement network-level controls such as firewall rules that restrict access to Midnight Commander functionality where possible, and disable unnecessary file manager extensions that rely on external command execution. Input validation should be strengthened by implementing proper escaping of shell metacharacters in filenames, and the application should be configured to run with minimal required privileges. Additionally, monitoring for unusual command execution patterns and implementing proper logging of file selection events can help detect exploitation attempts. This vulnerability aligns with CWE-78, which describes improper neutralization of special elements used in OS commands, and maps to ATT&CK technique T1059.001 for command and scripting interpreter. Organizations should also consider implementing principle of least privilege configurations and regular security assessments to prevent similar issues in other file management and shell-based applications.