CVE-2002-0333 in xtell
Summary
by MITRE
Directory traversal vulnerability in xtell (xtelld) 1.91.1 and earlier, and 2.x before 2.7, allows remote attackers to read files with short names, and local users to read more files using a symlink with a short name, via a .. in the TTY argument.
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Analysis
by VulDB Data Team • 12/17/2024
The vulnerability identified as CVE-2002-0333 represents a directory traversal flaw affecting the xtell (xtelld) service version 1.91.1 and earlier, as well as version 2.x before 2.7. This directory traversal vulnerability stems from inadequate input validation within the TTY argument processing mechanism of the service. The flaw specifically manifests when the service processes TTY arguments containing directory traversal sequences such as .. which allows unauthorized access to files outside the intended directory scope. The vulnerability affects both remote attackers who can exploit this through network connections and local users who can leverage symbolic links with short names to extend their access privileges. This type of vulnerability falls under the CWE-22 category of Improper Limitation of a Pathname to a Restricted Directory, which is a fundamental security weakness in path handling mechanisms.
The technical exploitation of this vulnerability occurs when the xtell service fails to properly sanitize or validate the TTY argument provided by users. When a malicious user submits a TTY argument containing directory traversal sequences like ../ or ..\, the service processes these sequences without proper validation, allowing access to files in parent directories. The vulnerability is particularly concerning because it affects systems where short filename handling is enabled, which was common in older operating systems and file systems. Local users can exploit this by creating symbolic links with short names that point to restricted files, effectively bypassing normal access controls. The impact extends beyond simple file reading as this vulnerability can potentially expose sensitive system information, configuration files, or user data that should remain protected.
The operational impact of CVE-2002-0333 is significant for systems running vulnerable versions of xtell service, as it can lead to unauthorized data access and potential information disclosure. Attackers can leverage this vulnerability to read system files, configuration data, or user files that contain sensitive information, potentially leading to further exploitation opportunities. The vulnerability's presence in both remote and local attack scenarios increases its threat profile, as it can be exploited by attackers with varying levels of access to the system. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and credential access, as unauthorized file reading can provide attackers with information needed for further compromise. The vulnerability also aligns with the technique of lateral movement through information gathering, as attackers can use the exposed files to identify system configurations, user accounts, or other sensitive data.
Mitigation strategies for CVE-2002-0333 should focus on immediate patching of affected systems with updated versions of xtell that properly validate TTY arguments and implement proper input sanitization. System administrators should ensure that all instances of xtell service are updated to versions 1.91.2 or later for version 1.x, and 2.7 or later for version 2.x. Additionally, implementing proper access controls and file system permissions can help limit the impact of potential exploitation. Network segmentation and firewall rules should be configured to restrict access to the xtell service to only trusted hosts. The implementation of input validation mechanisms that specifically check for directory traversal sequences in TTY arguments provides an additional layer of defense. Security monitoring should include detection of unusual file access patterns that might indicate exploitation attempts. Organizations should also consider implementing automated patch management systems to ensure timely deployment of security updates and maintain inventory of all systems running vulnerable services.