CVE-2018-0221 Explained : Impact and Mitigation

A security flaw has been identified in certain command-line interface (CLI) commands used for the Cisco Identity Services Engine (ISE). This vulnerability could be exploited by an authenticated attacker with local access. The attacker must possess valid administrator credentials for the affected device. The flaw is a result of incomplete validation of user input for specific CLI commands related to the ISE configuration. By exploiting this vulnerability, an attacker can inject commands into the underlying operating system or disrupt the user session, potentially leading to a hang or disconnection. To execute the attack, the attacker would need to authenticate as an administrative user, execute a specific CLI command, and input maliciously-crafted data as command parameters. Successful exploitation of this flaw could grant the attacker control over the lower-level Linux operating system. Additionally, it is possible that the attacker could cause the ISE user interface for the affected management session to hang or disconnect. This vulnerability is tracked under Cisco Bug IDs: CSCvg95479.

Understanding CVE-2018-0221

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.

What is CVE-2018-0221?

A security flaw in specific CLI commands for Cisco Identity Services Engine
Allows an authenticated attacker to inject commands or disrupt user sessions
Requires valid administrator credentials for the affected device

The Impact of CVE-2018-0221

Attacker can gain control over the lower-level Linux operating system
May cause the ISE user interface to hang or disconnect

Technical Details of CVE-2018-0221

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.

Vulnerability Description

Incomplete input validation of user input for certain CLI ISE configuration commands
Allows an attacker to inject commands into the operating system

Affected Systems and Versions

Product: Cisco Identity Services Engine
Version: Cisco Identity Services Engine

Exploitation Mechanism

Attacker authenticates as an administrative user
Executes a specific CLI command with crafted data
Can inject commands into the lower-level Linux operating system

Mitigation and Prevention

Immediate Steps to Take

Apply vendor-supplied patches or updates
Monitor network traffic for signs of malicious activity
Restrict access to administrative functions

Long-Term Security Practices

Regularly update and patch software and firmware
Conduct security training for administrators and users
Implement network segmentation and least privilege access controls

Patching and Updates

Check vendor advisories for patches and updates
Apply security best practices to prevent similar vulnerabilities