CVE-2005-0072 in zhcon
Summary
by MITRE
zhcon before 0.2 does not drop privileges before reading a user configuration file which allows local users to read arbitrary files.
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Analysis
by VulDB Data Team • 05/29/2019
The vulnerability described in CVE-2005-0072 affects zhcon versions prior to 0.2, representing a privilege escalation issue that stems from improper privilege management during configuration file processing. This flaw exists within the zhcon terminal emulator, which is designed to provide console-based Chinese character support for linux systems. The vulnerability is classified under the Common Weakness Enumeration category CWE-276, which deals with incorrect permissions for critical resources, and specifically relates to inadequate privilege dropping mechanisms in software applications.
The technical implementation of this vulnerability occurs when zhcon reads user configuration files without first dropping its elevated privileges. When a local user executes zhcon, the application typically runs with root privileges due to setuid bit configuration or similar privilege escalation mechanisms. However, before version 0.2, zhcon failed to relinquish these elevated privileges before processing user-supplied configuration data. This design flaw allows any local user to craft malicious configuration files that, when processed by zhcon, can result in arbitrary file reads from the system. The vulnerability specifically targets the configuration file parsing mechanism where user input is directly processed without proper privilege separation.
The operational impact of this vulnerability is significant for systems running affected versions of zhcon, as it enables local users to access files that would normally be restricted to root or other privileged users. Attackers can exploit this weakness to read sensitive system files, configuration data, and potentially gain information about the underlying system architecture. The vulnerability essentially allows privilege escalation from a regular user account to a level where arbitrary file system access becomes possible. This could lead to information disclosure, system reconnaissance, and potentially further exploitation opportunities within the compromised system environment.
Mitigation strategies for CVE-2005-0072 involve ensuring that zhcon properly drops privileges before processing any user configuration files. The most effective approach is to update to version 0.2 or later, where the privilege dropping mechanism has been implemented correctly. System administrators should also consider implementing additional security measures such as restricting write access to zhcon configuration directories and monitoring for unauthorized privilege escalation attempts. The vulnerability demonstrates the critical importance of proper privilege management in security-sensitive applications, aligning with ATT&CK technique T1068 which covers privilege escalation through local exploits. Organizations should also implement principle of least privilege practices and regularly audit applications for similar privilege-related vulnerabilities to prevent similar issues in other software components.