CVE-2018-0221 in Identity Services Engine
Summary
by MITRE
A vulnerability in specific CLI commands for the Cisco Identity Services Engine (ISE) could allow an authenticated, local attacker to perform command injection to the underlying operating system or cause a hang or disconnect of the user session. The attacker needs valid administrator credentials for the device. The vulnerability is due to incomplete input validation of user input for certain CLI ISE configuration commands. An attacker could exploit this vulnerability by authenticating as an administrative user, issuing a specific CLI command, and entering crafted, malicious user input for the command parameters. An exploit could allow the attacker to perform command injection to the lower-level Linux operating system. It is also possible the attacker could cause the ISE user interface for this management session to hang or disconnect. Cisco Bug IDs: CSCvg95479.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 02/17/2023
The vulnerability identified as CVE-2018-0221 affects Cisco Identity Services Engine (ISE) devices and represents a critical command injection flaw that can be exploited by authenticated local attackers. This vulnerability specifically targets the command-line interface functionality of the ISE platform, which serves as the primary management interface for network access control policies and user authentication services. The Cisco Identity Services Engine operates as a centralized policy enforcement point in enterprise networks, making this vulnerability particularly dangerous as it could compromise the core security infrastructure. The affected devices include various models of Cisco ISE appliances that utilize a Linux-based operating system as their underlying platform, with the vulnerability manifesting in the handling of specific configuration commands within the CLI environment.
The technical root cause of this vulnerability stems from incomplete input validation mechanisms within certain CLI commands of the ISE management interface. This weakness allows malicious input to bypass normal parameter sanitization processes, enabling attackers to inject arbitrary commands that execute within the underlying Linux operating system. The vulnerability is categorized as a command injection flaw that aligns with CWE-77, which specifically addresses command injection vulnerabilities where user-supplied data is not properly validated or escaped before being passed to system commands. When an authenticated administrator issues a specific CLI command with crafted input parameters, the system fails to properly sanitize the input before processing, creating an execution path that allows arbitrary code execution with the privileges of the ISE service account. This represents a classic privilege escalation vector that can be exploited through the principle of least privilege violation.
The operational impact of this vulnerability extends beyond simple command execution, as it provides attackers with multiple attack vectors for system compromise and service disruption. Successful exploitation can result in complete system compromise, allowing attackers to execute arbitrary commands with elevated privileges on the underlying Linux system, potentially leading to full administrative control of the ISE device. Additionally, the vulnerability can cause denial-of-service conditions by hanging or disconnecting user sessions, which can disrupt network access control services and potentially impact network connectivity for authenticated users. The ISE platform's role in managing network access policies makes this vulnerability particularly dangerous as it could allow attackers to modify access control lists, bypass authentication mechanisms, or even redirect network traffic through maliciously configured policies. This aligns with ATT&CK technique T1059, which covers command and scripting interpreter, and T1489, which addresses network denial of service, demonstrating how this vulnerability can be leveraged for both system compromise and service disruption.
Organizations affected by this vulnerability should implement immediate mitigations including applying the relevant Cisco security patches and updates, which address the input validation deficiencies in the affected CLI commands. Network segmentation and access control measures should be strengthened to limit administrative access to ISE devices, implementing the principle of least privilege for administrative accounts. Monitoring and logging should be enhanced to detect anomalous CLI command usage patterns, particularly around the vulnerable commands that are susceptible to input injection. The vulnerability also underscores the importance of regular security assessments and penetration testing of critical infrastructure components, as it demonstrates how seemingly benign administrative interfaces can contain critical security flaws. Security teams should also consider implementing network-based intrusion detection systems to monitor for suspicious command execution patterns that may indicate exploitation attempts, and maintain comprehensive incident response procedures for handling potential compromise of identity services infrastructure.