CVE-2001-1338 in IPC@CHIP Embedded-Webserver
Summary
by MITRE
Beck IPC GmbH IPC@CHIP TelnetD server generates different responses when given valid and invalid login names, which allows remote attackers to determine accounts on the system.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 06/13/2024
The vulnerability identified as CVE-2001-1338 affects the Beck IPC GmbH IPC@CHIP TelnetD server implementation, representing a classic account enumeration flaw that exposes system security through inconsistent error messaging. This vulnerability resides in the authentication mechanism of the telnet server component, where the system provides distinguishable responses based on whether a username exists within the system's user database. The flaw enables attackers to perform systematic account discovery by sending various username attempts and analyzing the server's response variations, effectively bypassing traditional brute force protections through intelligent reconnaissance.
The technical implementation of this vulnerability stems from improper error handling within the authentication subsystem. When valid usernames are submitted, the server responds with one message pattern, while invalid usernames trigger different response messages that reveal account existence. This differential response behavior directly violates security best practices for authentication systems, as it provides attackers with clear indicators about the validity of their guesses. The vulnerability operates at the application layer and specifically targets the telnet protocol implementation, making it exploitable through network-based attacks without requiring local system access or elevated privileges.
From an operational impact perspective, this vulnerability significantly weakens the security posture of systems running the affected IPC@CHIP TelnetD server, as it enables attackers to compile comprehensive user account lists for subsequent exploitation attempts. The information disclosure through response variations allows for targeted credential brute forcing, dictionary attacks, and social engineering operations, as attackers can focus their efforts on known valid accounts rather than conducting random guessing. This vulnerability particularly affects industrial control systems and embedded devices where telnet access is commonly enabled for administrative purposes, creating a substantial risk for critical infrastructure environments.
The flaw aligns with CWE-200, which addresses information exposure through improper error handling, and demonstrates characteristics consistent with ATT&CK technique T1078 for valid accounts and T1110 for credential access. Organizations should implement immediate mitigations including disabling unnecessary telnet services, implementing account lockout mechanisms, standardizing authentication responses regardless of account validity, and replacing the vulnerable telnet implementation with secure alternatives such as SSH. Additionally, network segmentation and access control measures should be enforced to limit exposure of vulnerable systems, while regular security audits should verify that authentication mechanisms provide consistent error responses to prevent similar enumeration attacks.