CVE-1999-1141 in Timeplex Router
Summary
by MITRE
ascom timeplex router allows remote attackers to obtain sensitive information or conduct unauthorized activities by entering debug mode through a sequence of ctrl-d characters.
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Analysis
by VulDB Data Team • 04/16/2026
The CVE-1999-1141 vulnerability affects the ascom timeplex router, representing a critical security flaw that allows remote attackers to gain unauthorized access to sensitive system information and conduct malicious activities. This vulnerability specifically exploits a debug mode functionality within the router's command interface, which can be triggered through a precise sequence of control characters. The flaw demonstrates a fundamental weakness in the device's access control mechanisms and authentication protocols, creating an unauthorized entry point that bypasses normal security boundaries.
The technical implementation of this vulnerability stems from the router's failure to properly validate or restrict access to its debug interface. When an attacker sends a sequence of ctrl-d characters to the device, the system responds by entering a debug mode that provides elevated privileges and access to internal system functions. This behavior violates the principle of least privilege and demonstrates poor input validation practices. The vulnerability is particularly concerning because it allows remote exploitation without requiring any authentication credentials, making it accessible to anyone who can establish a connection to the device's network interface.
From an operational perspective, this vulnerability creates significant risk for organizations relying on ascom timeplex routers for network infrastructure management. Attackers can leverage this flaw to obtain sensitive information including system configurations, user credentials, network topology details, and potentially gain control over network traffic routing. The debug mode access typically provides attackers with comprehensive system introspection capabilities, enabling them to identify additional vulnerabilities within the network infrastructure. This vulnerability aligns with CWE-284, which addresses improper access control issues, and represents a classic example of insecure direct object reference in network devices.
The impact of CVE-1999-1141 extends beyond simple information disclosure, as it provides attackers with a foothold for further malicious activities within the network environment. Once inside the debug mode, adversaries can manipulate routing tables, intercept network traffic, or establish persistent access points within the network infrastructure. This vulnerability can be exploited to conduct advanced persistent threats or facilitate lateral movement within the network. The attack vector demonstrates characteristics consistent with the attack technique described in MITRE ATT&CK framework under T1059 for command and control, and T1068 for exploit for privilege escalation.
Organizations should implement immediate mitigations including disabling debug interfaces on affected routers, implementing network segmentation to isolate critical infrastructure, and applying firmware updates if available. The vulnerability highlights the importance of secure device configuration practices and the necessity of regularly reviewing and updating network device access controls. Security monitoring should focus on detecting unusual network traffic patterns or unauthorized access attempts to network management interfaces. Additionally, network administrators should consider implementing network access control lists and restricting remote access to administrative functions to prevent unauthorized exploitation of similar vulnerabilities in network infrastructure devices.