CVE-2002-0105 in UnixWare
Summary
by MITRE
CDE dtlogin in Caldera UnixWare 7.1.0, and possibly other operating systems, allows local users to gain privileges via a symlink attack on /var/dt/Xerrors since /var/dt is world-writable.
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Analysis
by VulDB Data Team • 10/21/2024
The vulnerability described in CVE-2002-0105 represents a critical privilege escalation flaw within the Caldera UnixWare 7.1.0 operating system's CDE dtlogin component. This issue stems from improper handling of symbolic links in a world-writable directory structure, creating a persistent attack vector for local users to elevate their system privileges. The vulnerability specifically affects the Desktop Environment dtlogin utility which manages user authentication and session initialization within the CDE framework.
The technical flaw manifests through a symlink attack on the /var/dt/Xerrors file path where the dtlogin utility creates or modifies log files during the authentication process. Since the /var/dt directory is world-writable, malicious users can establish symbolic links that point to critical system files such as /etc/passwd or /etc/shadow, allowing them to manipulate authentication data or inject malicious content into system configuration files. This vulnerability directly maps to CWE-59 symbolic link attack and CWE-276 improper file permissions, as it exploits both weak directory permissions and improper file handling during the login process.
The operational impact of this vulnerability is significant as it allows any local user to gain elevated privileges without requiring authentication or prior access to system resources. Attackers can exploit this weakness to modify user accounts, escalate their privileges to root level, or manipulate system security settings. The attack requires minimal resources and can be executed through standard user-level commands, making it particularly dangerous in multi-user environments where privilege separation is critical. This vulnerability undermines the fundamental security model of the operating system by allowing unauthorized privilege escalation through a simple file system manipulation technique.
Mitigation strategies should focus on immediate permission adjustments to prevent world-writable directories from being used in critical system paths. System administrators should ensure that the /var/dt directory and its contents are properly secured with restrictive permissions, ideally owned by root with read-only access for system processes. The recommended remediation includes implementing proper file system permissions, removing world-writable attributes from critical directories, and potentially patching the CDE dtlogin component to validate symbolic links before processing them. Additionally, monitoring for unauthorized symbolic link creation in system directories should be implemented as part of the overall security posture. This vulnerability aligns with ATT&CK technique T1068 privilege escalation through local exploitation and highlights the importance of proper file system permissions in maintaining system integrity.