CVE-2000-0698 in Minicom
Summary
by MITRE
Minicom 1.82.1 and earlier on some Linux systems allows local users to create arbitrary files owned by the uucp user via a symlink attack.
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Analysis
by VulDB Data Team • 11/30/2024
The vulnerability identified as CVE-2000-0698 represents a significant security flaw in the minicom terminal emulator version 1.82.1 and earlier installations on linux systems. This issue stems from improper handling of symbolic links during file operations, creating a privilege escalation vector that allows local attackers to manipulate file ownership. The vulnerability specifically affects systems where minicom is installed with setuid permissions, enabling it to execute with elevated privileges. When minicom processes certain file operations, it fails to properly validate or sanitize symbolic link references, creating an opportunity for malicious users to exploit the system's file creation mechanisms. The attack leverages the uucp user context, which is typically used for dial-up modem access and system communication protocols, making this vulnerability particularly concerning for systems utilizing such services.
The technical implementation of this vulnerability involves a classic symlink attack pattern where an attacker creates a symbolic link pointing to a target file that minicom would normally create or modify. When minicom executes its operations, it follows the symbolic link and creates or modifies files in unexpected locations, effectively transferring ownership to the uucp user account. This flaw falls under the category of improper file handling and privilege management, with direct implications for the principle of least privilege and proper access controls. The vulnerability demonstrates a failure in input validation and file system operation security, where the application does not adequately verify the integrity of file paths before attempting operations. This weakness can be classified under CWE-59 and CWE-276, representing improper file permissions and improper privilege management respectively, both of which are fundamental security concerns in system administration.
The operational impact of CVE-2000-0698 extends beyond simple file ownership manipulation, as it can enable more sophisticated attacks within the compromised system. An attacker with local access can leverage this vulnerability to create files that persist beyond the initial attack vector, potentially establishing backdoors or modifying system files that require uucp user privileges. The attack requires local system access but does not need network connectivity, making it particularly dangerous in environments where physical access is possible or where other local vulnerabilities have been exploited. This vulnerability can be particularly damaging in multi-user systems where uucp privileges are used for legitimate system functions, as it allows attackers to gain unauthorized access to resources that should remain protected. The vulnerability also demonstrates a broader issue with setuid applications and their potential for exploitation, aligning with ATT&CK technique T1548.001 for privilege escalation through setuid binaries.
Mitigation strategies for this vulnerability involve immediate patching of affected minicom installations to versions that properly handle symbolic links and implement proper file system validation. System administrators should ensure that minicom is updated to the latest stable release that addresses this specific flaw. Additionally, implementing proper file system permissions and ensuring that setuid binaries are properly audited can help prevent similar issues. The recommended approach includes disabling unnecessary setuid permissions on terminal emulators and other system utilities, as well as implementing proper file system monitoring to detect unauthorized file creation patterns. Organizations should also consider implementing privilege separation techniques and ensuring that applications do not execute with elevated privileges unless absolutely necessary. This vulnerability highlights the importance of proper input validation and file system security practices, which are fundamental to maintaining system integrity and preventing unauthorized access. The fix typically involves updating the application code to properly check for symbolic links before file operations and to validate all file paths used in system operations.