CVE-2002-1558 in ONS15327
Summary
by MITRE
Cisco ONS15454 and ONS15327 running ONS before 3.4 have an account for the VxWorks Operating System in the TCC, TCC+ and XTC that cannot be changed or disabled, which allows remote attackers to gain privileges by connecting to the account via Telnet.
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Analysis
by VulDB Data Team • 05/29/2019
The vulnerability identified as CVE-2002-1558 affects Cisco ONS 15454 and ONS 15327 telecommunications equipment operating with ONS software versions prior to 3.4. These devices utilize the VxWorks operating system within their TCC, TCC+, and XTC modules, creating a persistent security weakness that directly impacts the device's authentication and privilege management mechanisms. The flaw resides in the default configuration where a specific VxWorks account remains permanently enabled and unchanged, providing unauthorized access vectors to attackers who can exploit this weakness through network connections.
This security weakness represents a fundamental failure in the principle of least privilege and proper access control implementation. The vulnerable account cannot be modified or disabled through normal administrative procedures, creating a permanent backdoor that remains active regardless of security policies or configuration changes. The vulnerability specifically allows remote attackers to establish Telnet connections to the device using this hardcoded account, effectively bypassing all normal authentication mechanisms and granting immediate administrative privileges. This represents a critical design flaw that violates the security principle of secure defaults and proper credential management.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it provides attackers with complete administrative control over the telecommunications infrastructure. Once an attacker successfully connects via Telnet using the hardcoded credentials, they can modify network configurations, access sensitive operational data, disrupt services, and potentially use the compromised device as a pivot point for attacking other systems within the network. The remote nature of the attack means that an attacker does not require physical access to the device, significantly expanding the threat surface and attack vectors available to malicious actors. This vulnerability directly aligns with CWE-798, which addresses the use of hardcoded credentials, and represents a classic example of insecure default configuration that violates fundamental security practices.
Mitigation strategies for this vulnerability require immediate implementation of several security measures including immediate firmware upgrades to ONS software version 3.4 or later, which should address the hardcoded account issue. Network administrators should also implement strict network segmentation and access controls to limit Telnet access to only authorized personnel and systems. Additional protective measures include disabling Telnet services entirely in favor of more secure protocols such as SSH, implementing network monitoring to detect unauthorized Telnet connections, and conducting comprehensive security assessments to identify any potential exploitation attempts. Organizations should also consider implementing intrusion detection systems that can identify attempts to connect to the hardcoded account, and establish proper change management procedures to ensure that default configurations are properly secured. This vulnerability demonstrates the critical importance of proper credential management and secure default configurations as outlined in the NIST Cybersecurity Framework and aligns with ATT&CK technique T1078 for valid accounts and T1046 for network service scanning.