CVE-2018-0417 in Wireless LAN Controller
Summary
by MITRE
A vulnerability in TACACS authentication with Cisco Wireless LAN Controller (WLC) Software could allow an authenticated, local attacker to perform certain operations within the GUI that are not normally available to that user on the CLI. The vulnerability is due to incorrect parsing of a specific TACACS attribute received in the TACACS response from the remote TACACS server. An attacker could exploit this vulnerability by authenticating via TACACS to the GUI on the affected device. A successful exploit could allow an attacker to create local user accounts with administrative privileges on an affected WLC and execute other commands that are not allowed from the CLI and should be prohibited.
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Analysis
by VulDB Data Team • 05/30/2023
The vulnerability identified as CVE-2018-0417 represents a critical authorization flaw within Cisco Wireless LAN Controller software that undermines the security model of TACACS-based authentication. This weakness specifically affects the parsing mechanism of TACACS attributes, creating a pathway for authenticated local attackers to escalate their privileges and access restricted GUI functionalities that are normally locked down from command-line interface access. The vulnerability stems from improper handling of TACACS response attributes, where the system fails to correctly validate or sanitize the authorization data received from remote TACACS servers, leading to potential privilege escalation and unauthorized administrative actions.
The technical implementation of this vulnerability occurs when a malicious user successfully authenticates through TACACS to the WLC GUI interface, exploiting the flawed attribute parsing logic. This flaw allows the attacker to manipulate or inject specific TACACS attributes that, when improperly processed, grant elevated privileges beyond what would normally be permitted. The vulnerability specifically enables the creation of local administrative user accounts and execution of commands that are typically restricted from CLI access, effectively bypassing the intended security boundaries between different user roles and privilege levels. This represents a direct violation of the principle of least privilege and demonstrates a failure in access control validation mechanisms within the TACACS integration framework.
The operational impact of CVE-2018-0417 extends beyond simple privilege escalation to encompass potential full system compromise and unauthorized administrative control over wireless network infrastructure. An attacker exploiting this vulnerability could establish persistent administrative access points, modify wireless configurations, intercept network traffic, and potentially disrupt wireless services for legitimate users. The vulnerability's location within the GUI authentication processing layer means that even users with limited privileges could gain administrative capabilities, creating a significant risk for organizations relying on TACACS for centralized authentication management. This flaw particularly affects enterprise wireless networks where WLCs serve as critical infrastructure components for network access control and security enforcement.
Organizations affected by CVE-2018-0417 should implement immediate mitigations including applying the latest Cisco security patches and updates, reviewing and tightening TACACS server configurations, and implementing additional access controls around WLC management interfaces. Network administrators should consider disabling unnecessary GUI access when CLI access is sufficient for administrative tasks, and establish monitoring for unusual administrative account creation or privilege escalation attempts. The vulnerability aligns with CWE-284 which addresses improper access control, and maps to ATT&CK technique T1078 for valid accounts and T1484 for abuse of credentials, highlighting the need for comprehensive monitoring and access control measures. Security teams should also review their TACACS server configurations to ensure proper attribute validation and implement network segmentation to limit access to WLC management interfaces to authorized personnel only.