CVE-2001-0994 in ForeThought
Summary
by MITRE
Marconi ForeThought 7.1 allows remote attackers to cause a denial of service by causing both telnet sessions to be locked via unusual input (e.g., from a port scanner), which prevents others from logging into the device.
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Analysis
by VulDB Data Team • 06/04/2018
The vulnerability described in CVE-2001-0994 affects the Marconi ForeThought 7.1 network device, representing a significant denial of service weakness that compromises system availability. This issue manifests when remote attackers exploit improper input handling within the telnet service implementation, specifically targeting the device's authentication and session management mechanisms. The flaw enables attackers to manipulate telnet sessions in a way that locks them, effectively preventing legitimate users from establishing new connections to the device. The vulnerability operates through unconventional input sequences that are typically generated by port scanning tools or automated exploitation frameworks, making it particularly dangerous in environments where network reconnaissance activities occur.
The technical root cause of this vulnerability lies in the inadequate validation and handling of input parameters within the telnet service of the ForeThought 7.1 device. When unusual or malformed input data is received through telnet connections, the system fails to properly process these inputs and instead enters a state where all telnet sessions become locked or blocked. This behavior stems from a lack of proper input sanitization and session management protocols within the device's network services implementation. The flaw essentially creates a condition where legitimate authentication attempts are either rejected or indefinitely delayed, resulting in complete service unavailability for authorized users who attempt to access the device. This type of vulnerability aligns with CWE-20, which describes improper input validation, and represents a classic example of how insufficient error handling can lead to system-wide availability issues.
The operational impact of CVE-2001-0994 extends beyond simple service disruption to potentially compromise the entire network infrastructure managed by the affected device. When telnet sessions become locked, administrators lose the ability to remotely access and manage the device, which can lead to extended downtime for network operations and potentially require physical access to restore functionality. This vulnerability is particularly concerning because it can be triggered automatically by common network scanning tools, meaning that unauthorized access attempts can occur without direct human intervention. The attack vector demonstrates characteristics consistent with the attack pattern described in the MITRE ATT&CK framework under the technique of "Denial of Service" where adversaries seek to make systems unavailable to legitimate users. Network administrators may find their devices become inaccessible during routine security assessments or when under attack from automated scanning tools, leading to operational disruptions and potential security incidents.
Mitigation strategies for this vulnerability should focus on implementing robust input validation mechanisms and session management controls within the telnet service implementation. Organizations should consider disabling unnecessary telnet services and implementing secure remote access protocols such as SSH instead of relying on telnet for device management. Network segmentation and access control measures can help limit the potential impact of such attacks by restricting unauthorized access attempts to critical infrastructure. Additionally, implementing rate limiting and connection monitoring can help detect and prevent the exploitation of this vulnerability by automated scanning tools. The solution approach aligns with industry best practices for securing network services and addresses the fundamental weakness in input handling that enables this denial of service condition. Regular security assessments and vulnerability scanning should be conducted to identify similar weaknesses in network infrastructure components that may be susceptible to similar exploitation patterns.