CVE-2018-0115 in StarOS
Summary
by MITRE
A vulnerability in the CLI of the Cisco StarOS operating system for Cisco ASR 5000 Series routers could allow an authenticated, local attacker to execute arbitrary commands with root privileges on an affected host operating system. The vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by injecting malicious command arguments into a vulnerable CLI command. A successful exploit could allow the attacker to execute arbitrary commands with root privileges. To exploit this vulnerability, the attacker would need to authenticate to the affected system by using valid administrator credentials. Cisco Bug IDs: CSCvf93332.
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Analysis
by VulDB Data Team • 02/01/2021
The vulnerability identified as CVE-2018-0115 represents a critical privilege escalation flaw within the Cisco StarOS operating system that specifically affects Cisco ASR 5000 Series routers. This security weakness resides in the command line interface implementation where insufficient input validation mechanisms fail to properly sanitize user-supplied parameters. The vulnerability stems from a fundamental design flaw that allows malicious command injection attacks to bypass normal security controls and execute arbitrary code with the highest possible system privileges. The affected system operates with a CLI that does not adequately validate or filter input parameters, creating an environment where crafted malicious inputs can be interpreted and executed as legitimate commands by the underlying operating system.
The technical exploitation of this vulnerability requires an authenticated attacker who possesses valid administrator credentials to access the system. Once authenticated, the attacker can leverage the insufficient input validation by injecting specially crafted command arguments into vulnerable CLI commands. This injection technique allows the attacker to manipulate the command execution flow and ultimately gain root-level access to the operating system. The vulnerability operates at the command processing level where user inputs are not properly sanitized before being passed to system execution functions, enabling a form of command injection attack that bypasses standard authentication and authorization controls. The flaw specifically affects the CLI parser functionality and demonstrates poor input handling practices that are consistent with CWE-77 and CWE-89 categories related to command injection vulnerabilities.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass complete system compromise and potential network-wide disruption. An attacker with root privileges can modify system configurations, install malicious software, access sensitive network data, and potentially establish persistent backdoors within the router infrastructure. This vulnerability directly impacts the integrity and availability of the network infrastructure as the compromised router can be used to redirect traffic, perform man-in-the-middle attacks, or serve as a pivot point for further network infiltration. The affected Cisco ASR 5000 Series routers operate in critical network environments where such compromise could lead to significant service disruptions and security breaches that align with ATT&CK technique T1059.004 for command and script injection.
Mitigation strategies for CVE-2018-0115 should prioritize immediate implementation of Cisco's recommended security patches and firmware updates that address the input validation deficiencies in the CLI processing. Network administrators must ensure that all affected systems receive the latest security updates from Cisco to remediate the vulnerability. Additional defensive measures include implementing strict access controls and limiting administrator privileges to only necessary personnel, employing network segmentation to isolate critical router infrastructure, and monitoring CLI access logs for suspicious command patterns. The vulnerability demonstrates the importance of input validation and proper sanitization of user-supplied data within system interfaces, which aligns with security best practices outlined in NIST SP 800-160 and ISO 27001 standards. Organizations should also consider implementing network monitoring solutions that can detect anomalous CLI usage patterns and provide alerts for potential exploitation attempts. Regular security assessments and penetration testing should be conducted to identify similar input validation weaknesses in other network components and ensure comprehensive protection against command injection attacks.