CVE-2000-0212 in InterAccess TelnetD Server
Summary
by MITRE
InterAccess TelnetD Server 4.0 allows remote attackers to conduct a denial of service via malformed terminal client configuration information.
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Analysis
by VulDB Data Team • 04/20/2026
The vulnerability identified as CVE-2000-0212 affects InterAccess TelnetID Server version 4.0, representing a critical denial of service weakness that can be exploited by remote attackers through the manipulation of terminal client configuration data. This flaw resides within the server's handling of client connection parameters and configuration information, specifically when processing malformed terminal client configurations. The vulnerability stems from inadequate input validation mechanisms within the Telnet server implementation, allowing malicious actors to craft specially formatted client configuration data that triggers unexpected behavior in the server software. The affected system fails to properly sanitize or validate incoming terminal client configuration parameters, creating an opportunity for attackers to disrupt legitimate service availability.
The technical implementation of this vulnerability demonstrates a classic buffer over-read or improper state handling issue within the Telnet server's client configuration processing logic. When the server receives malformed terminal client configuration information, it attempts to parse and process these parameters without sufficient validation checks, leading to unpredictable execution paths that can result in service termination or system instability. The flaw operates at the application layer of the network stack, specifically targeting the telnet protocol implementation within the InterAccess server software. This vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-122, which covers buffer overflow vulnerabilities in heap-based memory structures. The attack vector requires only network connectivity to the target server and does not necessitate authentication or specialized privileges, making it particularly dangerous for publicly accessible telnet services.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the overall availability and reliability of network services that depend on the affected Telnet server. Remote attackers can exploit this weakness to repeatedly crash the server, forcing administrators to restart services and potentially causing extended downtime for legitimate users. The vulnerability affects systems where the TelnetID Server 4.0 is deployed as a primary authentication or connectivity service, particularly in enterprise environments where telnet services are still utilized for legacy system access. Organizations may experience cascading effects where the denial of service impacts dependent services or applications that rely on the telnet server for authentication or connectivity. From an operational security perspective, this vulnerability represents a significant risk to service availability and can be exploited as part of broader attack campaigns targeting network infrastructure components.
Mitigation strategies for CVE-2000-0212 should prioritize immediate patching or upgrading of affected InterAccess TelnetID Server installations to versions that address the malformed configuration handling issue. Network administrators should implement firewall rules to restrict access to telnet services where possible, particularly for external networks, and consider implementing intrusion detection systems to monitor for suspicious client configuration patterns. The solution architecture should incorporate proper input validation and sanitization mechanisms to prevent malformed data from causing service disruption. Additionally, organizations should consider migrating away from telnet-based services to more secure alternatives such as ssh protocols, which provide better authentication mechanisms and are less susceptible to similar denial of service vulnerabilities. This vulnerability also highlights the importance of following ATT&CK framework concepts related to privilege escalation and defense evasion through service disruption techniques, as attackers may use similar approaches to compromise system availability and access to network resources.