CVE-2001-1340 in IPC@Chip Telnetd Server
Summary
by MITRE
Beck GmbH IPC@Chip TelnetD service supports only one connection and does not disconnect a user who does not complete the login process, which allows remote attackers to lock out the administrator account by connecting to the service.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 06/14/2024
The vulnerability identified as CVE-2001-1340 affects the Beck GmbH IPC@Chip TelnetD service, representing a classic resource exhaustion and authentication bypass flaw that emerged in networked industrial control systems during the early 2000s. This issue demonstrates how embedded network services in industrial environments often lacked proper connection management and authentication mechanisms, creating significant security risks for critical infrastructure deployments. The vulnerability resides in the service's inability to properly handle concurrent connections and maintain session state, particularly during authentication phases.
The technical flaw manifests as a single connection limitation combined with inadequate session cleanup mechanisms within the TelnetD service implementation. When a remote attacker establishes a connection to the service, the system accepts the connection but fails to properly terminate or reclaim resources when the user fails to complete the authentication process. This design flaw creates a resource exhaustion condition where the service maintains active connection slots that cannot be released until the connection times out or is manually terminated. The attacker can exploit this by repeatedly initiating connections without completing authentication, thereby consuming all available connection slots and effectively locking out legitimate users.
The operational impact of this vulnerability extends beyond simple denial of service to create a more serious security compromise within industrial control environments. The administrator account becomes inaccessible to legitimate users, which can severely disrupt operations in critical infrastructure scenarios where remote access is essential for system maintenance and monitoring. This vulnerability directly violates the principle of least privilege and proper resource management as outlined in cybersecurity frameworks, creating a persistent access control weakness that can be exploited by attackers with minimal technical expertise. The issue also aligns with CWE-400, which addresses improper resource management and the potential for denial of service through resource exhaustion attacks.
From an adversarial perspective, this vulnerability represents a low-effort, high-impact attack vector that can be executed by anyone with network access to the affected service. The attack does not require sophisticated techniques or deep system knowledge, making it particularly dangerous in operational technology environments where security awareness may be limited. The Telnet protocol itself, while providing essential remote access capabilities, lacks modern authentication security features, and this vulnerability compounds the inherent weaknesses of the protocol in industrial settings. The attack pattern follows ATT&CK technique T1110.003, which involves credential stuffing and account lockout methods to gain unauthorized access to systems.
The mitigation strategies for this vulnerability should address both immediate operational concerns and long-term security improvements. Organizations should implement connection timeout mechanisms and proper session cleanup procedures within the TelnetD service configuration. Network segmentation and access control lists should be deployed to limit exposure of the affected service to trusted networks only. Additionally, implementing alternative authentication mechanisms such as SSH or secure remote access protocols would provide better protection against similar vulnerabilities. The solution should also include monitoring and alerting capabilities to detect unusual connection patterns that might indicate exploitation attempts. Regular security assessments of industrial control systems should be conducted to identify similar resource management flaws that could create similar access control issues. This vulnerability serves as a reminder of the importance of proper resource management in embedded systems and the need for robust authentication mechanisms in critical infrastructure environments where system availability and security are paramount considerations.