CVE-2002-0134 in Avirt Gateway Suite
Summary
by MITRE
Telnet proxy in Avirt Gateway Suite 4.2 does not require authentication for connecting to the proxy system itself, which allows remote attackers to list file contents of the proxy and execute arbitrary commands via a "dos" command.
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Analysis
by VulDB Data Team • 09/22/2025
The vulnerability identified as CVE-2002-0134 represents a critical security flaw in the Avirt Gateway Suite 4.2 telnet proxy implementation that fundamentally undermines the system's access control mechanisms. This weakness exists within the proxy component that handles telnet connections, where the authentication process fails to properly validate user credentials before granting access to the underlying proxy system. The absence of authentication requirements creates an exploitable entry point that allows unauthorized remote attackers to gain elevated privileges and execute malicious operations. The vulnerability specifically manifests through a "dos" command that enables attackers to enumerate file system contents and execute arbitrary commands, effectively providing complete control over the affected system.
This technical flaw directly maps to CWE-287, which addresses improper authentication issues in software systems, and aligns with ATT&CK technique T1110.001 for credential access through brute force or default credentials. The vulnerability stems from inadequate input validation and access control implementation within the telnet proxy service, where the system fails to properly authenticate users before permitting access to administrative functions. The flaw demonstrates a classic lack of principle of least privilege enforcement, as the proxy service does not require proper authentication before allowing access to its core functionality. Attackers can exploit this weakness by simply connecting to the telnet proxy service without providing valid credentials, immediately gaining access to sensitive system information and execution capabilities.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to perform comprehensive reconnaissance of the proxy system's file structure and execute arbitrary code with the privileges of the proxy service. This capability allows threat actors to escalate their privileges, potentially leading to full system compromise and persistence within the network environment. The vulnerability affects organizations that deploy Avirt Gateway Suite 4.2, particularly those with exposed telnet proxy services that lack proper network segmentation or additional access controls. The remote nature of the exploit means that attackers can leverage this vulnerability from outside the organization's network perimeter, making it particularly dangerous for systems with public internet exposure. The consequences include data theft, system compromise, and potential lateral movement within the network.
Mitigation strategies for CVE-2002-0134 should focus on implementing proper authentication mechanisms for the telnet proxy service, including mandatory credential validation before granting access to proxy functionality. Organizations should immediately disable or remove the vulnerable telnet proxy service if it is not essential for operations, or implement network segmentation to restrict access to trusted administrative networks only. The solution requires enforcing strong authentication controls, such as requiring valid user credentials before allowing access to the proxy system, and implementing proper access control lists that limit who can connect to the proxy service. Additionally, administrators should consider replacing the vulnerable telnet proxy with more secure alternatives that properly enforce authentication and authorization controls. Regular security audits should verify that all proxy services require proper authentication and that access controls are appropriately configured to prevent unauthorized access to system resources. The implementation of logging and monitoring for proxy service access attempts will help detect and respond to potential exploitation attempts.