CVE-2003-0537 in Liece Emacs IRC Client
Summary
by MITRE
The liece Emacs IRC client 2.0+0.20030527 and earlier creates temporary files insecurely, which could allow local users to overwrite arbitrary files as other users.
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Analysis
by VulDB Data Team • 06/29/2021
The liece emacs irc client version 2.0+0.20030527 and earlier contains a critical insecure temporary file creation vulnerability that presents significant security risks for local users. This flaw stems from the application's improper handling of temporary file generation during its operation, creating opportunities for privilege escalation and arbitrary file overwrite attacks. The vulnerability specifically affects systems where the irc client runs with elevated privileges or where multiple users share the same system environment, making it particularly dangerous in multi-user scenarios.
The technical implementation of this vulnerability resides in the insecure creation of temporary files within the liece application's codebase. When the irc client generates temporary files, it fails to employ proper secure file creation mechanisms that would prevent predictable file paths or insecure permissions. This insecure practice typically involves creating temporary files in world-writable directories such as /tmp or /var/tmp without proper file permissions or secure naming conventions. Attackers can exploit this by creating symbolic links or by pre-creating files in the expected temporary locations, allowing them to overwrite files owned by other users or even the root user when the application runs with elevated privileges.
The operational impact of this vulnerability extends beyond simple file overwrites, as it can enable privilege escalation attacks within the system. When local users can manipulate temporary files created by liece, they gain the ability to modify critical system files, configuration files, or even binaries that the application might attempt to write to during its operation. This creates a potential attack vector for persistent system compromise, where malicious users could plant backdoors or modify system components to maintain access. The vulnerability is particularly concerning in environments where the liece client runs with higher privileges, such as when executed by system administrators or in automated processes.
This vulnerability maps directly to CWE-377: Insecure Temporary File and CWE-378: Creation of Temporary File With Insecure Permissions, both of which are categorized under the broader weakness of insecure file handling practices. From an attack perspective, this vulnerability aligns with ATT&CK technique T1059.006 for command and scripting interpreter, and potentially T1548.001 for abuse of privileges, as attackers could leverage the insecure temporary file creation to execute malicious code with elevated privileges. The attack surface is widened by the fact that this is a local privilege escalation vector that requires no network connectivity and can be exploited through simple file system manipulation techniques.
Mitigation strategies for this vulnerability include immediate patching of the liece client to version 2.0+0.20030528 or later, which contains the necessary secure temporary file creation fixes. System administrators should also implement proper file permissions and directory access controls to prevent attackers from creating symbolic links in temporary directories. Additionally, the application should be configured to create temporary files in secure locations with proper permissions, using secure file creation functions that prevent predictable naming and ensure appropriate access controls. Regular security audits of application temporary file handling practices should be conducted, and users should be educated about the risks of running applications with elevated privileges when such vulnerabilities exist. Organizations should also consider implementing file integrity monitoring solutions to detect unauthorized modifications to critical system files that might result from exploitation of this vulnerability.