CVE-1999-1092 in TIN
Summary
by MITRE
tin 1.40 creates the .tin directory with insecure permissions, which allows local users to read passwords from the .inputhistory file.
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Analysis
by VulDB Data Team • 04/19/2026
The vulnerability described in CVE-1999-1092 affects the tin newsreader software version 1.40, specifically targeting the creation of configuration directories with insecure permission settings. This flaw represents a classic privilege escalation and information disclosure vulnerability that exploits weak file system permissions to compromise user security. The tin software, which serves as a newsreader for usenet newsgroups, creates a hidden directory named .tin in the user's home directory during its initialization process. When this directory is created with overly permissive permissions, it exposes sensitive information stored within related files, particularly the .inputhistory file that contains command history and potentially sensitive data.
The technical implementation of this vulnerability stems from the improper handling of directory creation permissions within the tin software. When the application initializes, it creates the .tin directory without setting appropriate access controls, typically defaulting to world-readable permissions. This allows any local user on the system to access the directory and its contents, including the .inputhistory file that may contain command sequences, configuration settings, or potentially sensitive information entered by the user. The insecure permissions create a direct path for privilege escalation attacks where local users can read data that should remain confidential to the legitimate user.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable more sophisticated attacks. Local users who can read the .inputhistory file may gain access to command sequences that could reveal system configuration details, network settings, or other sensitive operational data. This information could be leveraged to understand the user's interaction patterns with the newsreader, potentially aiding in social engineering attacks or further exploitation attempts. The vulnerability particularly affects environments where multiple users share the same system, as it creates a vector for unauthorized information access across user accounts. According to CWE classification, this represents a weakness in permission handling and access control, specifically CWE-276, which deals with improper file permissions that allow unauthorized access to sensitive data.
Security professionals should consider this vulnerability in the context of the ATT&CK framework, particularly under the techniques related to privilege escalation and credential access. The vulnerability aligns with T1068, which involves exploiting weaknesses in privilege management, and T1552, which covers unauthorized access to credentials and secrets. The flaw demonstrates how seemingly innocuous configuration management can create significant security implications. System administrators should implement immediate mitigations by ensuring proper directory permissions are set during the tin software installation process, typically requiring that the .tin directory be created with restrictive permissions such as 700 (read, write, execute for owner only). Additionally, regular security audits should verify that no insecure directories exist in user home directories, and that proper access controls are maintained across all system components.
The remediation approach for this vulnerability requires both immediate and long-term security measures to address the root cause of the insecure permission handling. Immediate fixes should involve modifying the tin software installation process to ensure that the .tin directory is created with proper permissions, typically restricting access to the owning user only. Long-term solutions should include implementing automated security checks that verify directory permissions during system maintenance cycles, and establishing security policies that mandate proper file system access controls for all applications. This vulnerability highlights the critical importance of secure coding practices and proper permission management in preventing unauthorized access to sensitive information, particularly in multi-user environments where privilege separation is essential for maintaining system security.