CVE-2018-0122 in StarOS
Summary
by MITRE
A vulnerability in the CLI of the Cisco StarOS operating system for Cisco ASR 5000 Series Aggregation Services Routers could allow an authenticated, local attacker to overwrite system files that are stored in the flash memory of an affected system. The vulnerability is due to insufficient validation of user-supplied input by the affected operating system. An attacker could exploit this vulnerability by injecting crafted command arguments into a vulnerable CLI command for the affected operating system. A successful exploit could allow the attacker to overwrite or modify arbitrary files that are stored in the flash memory of an affected system. To exploit this vulnerability, the attacker would need to authenticate to an affected system by using valid administrator credentials. Cisco Bug IDs: CSCvf93335.
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Analysis
by VulDB Data Team • 02/02/2021
The vulnerability identified as CVE-2018-0122 affects the Cisco StarOS operating system running on Cisco ASR 5000 Series Aggregation Services Routers, representing a critical local privilege escalation issue that undermines the integrity of system file management. This weakness exists within the command line interface component of the operating system where insufficient input validation mechanisms fail to properly sanitize user-supplied arguments before processing them. The flaw allows authenticated attackers with administrative privileges to manipulate the system's flash memory through crafted command sequences, potentially compromising the router's operational integrity and security posture. The vulnerability stems from inadequate parameter validation within the CLI processing pipeline, creating a path for malicious input injection that bypasses normal system safeguards.
The technical exploitation of this vulnerability requires an attacker to possess valid administrator credentials, establishing a baseline authentication requirement that limits the attack surface but does not eliminate the risk entirely. Once authenticated, the attacker can leverage the insufficient input validation to inject malicious command arguments that target the flash memory storage areas where critical system files reside. This allows for arbitrary file modification or overwriting operations that can fundamentally alter the router's behavior and potentially introduce persistent backdoors or malicious code execution capabilities. The vulnerability specifically targets the file system management functions within the StarOS environment, where legitimate administrative commands can be subverted through carefully crafted inputs that exploit the lack of proper sanitization checks.
The operational impact of this vulnerability extends beyond simple file modification, as it creates potential pathways for more sophisticated attacks that could compromise the entire router infrastructure. An attacker who successfully exploits this vulnerability could modify critical system files such as configuration data, firmware components, or security policy definitions, potentially leading to complete system compromise or denial of service conditions. The ability to overwrite flash-stored files represents a significant threat to network infrastructure reliability, as it allows for persistent modifications that could survive system reboots and normal operational cycles. This vulnerability directly impacts the availability, integrity, and confidentiality of the affected network services, potentially enabling attackers to establish long-term access points within the network infrastructure.
Mitigation strategies for CVE-2018-0122 should focus on implementing comprehensive input validation controls within the CLI processing framework, aligning with established security practices and standards such as those defined in CWE-20 for input validation weaknesses. Network administrators should ensure that all system updates and patches are applied promptly to address the identified vulnerability, as Cisco has released specific fixes for this issue through their security advisory process. The implementation of least privilege principles and enhanced monitoring of administrative activities can help detect anomalous CLI usage patterns that might indicate exploitation attempts. Additionally, regular security assessments and vulnerability scanning should be conducted to identify potential input validation gaps in other system components, following ATT&CK framework principles for privilege escalation techniques that leverage command injection vulnerabilities. Organizations should also implement robust backup and recovery procedures to ensure rapid restoration of system integrity if exploitation occurs, while maintaining detailed audit logs of all administrative activities for forensic analysis purposes.