CVE-2018-0238 in Unified Computing System
Summary
by MITRE
A vulnerability in the role-based resource checking functionality of the Cisco Unified Computing System (UCS) Director could allow an authenticated, remote attacker to view unauthorized information for any virtual machine in the UCS Director end-user portal and perform any permitted operations on any virtual machine. The permitted operations can be configured for the end user on the virtual machines with either of the following settings: The virtual machine is associated to a Virtual Data Center (VDC) that has an end user self-service policy attached to the VDC. The end user role has VM Management Actions settings configured under User Permissions. This is a global configuration, so all the virtual machines visible in the end-user portal will have the VM management actions available. The vulnerability is due to improper user authentication checks. An attacker could exploit this vulnerability by logging in to the UCS Director with a modified username and valid password. A successful exploit could allow the attacker to gain visibility into and perform actions against all virtual machines in the UCS Director end-user portal of the affected system. This vulnerability affects Cisco Unified Computing System (UCS) Director releases 6.0 and 6.5 prior to patch 3 that are in a default configuration. Cisco Bug IDs: CSCvh53501.
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Analysis
by VulDB Data Team • 03/03/2023
The vulnerability identified as CVE-2018-0238 resides within the role-based resource checking mechanisms of Cisco Unified Computing System UCS Director, representing a critical authorization flaw that undermines the system's security model. This weakness specifically targets the authentication validation processes that should enforce strict access controls between users and virtual machine resources within the UCS Director environment. The vulnerability stems from inadequate implementation of user authentication checks, creating a path for authenticated attackers to bypass intended access restrictions and gain unauthorized visibility into virtual machine configurations and operations. The flaw affects systems running UCS Director releases 6.0 and 6.5 prior to patch 3, particularly when deployed in default configurations, making it a widespread concern across organizations utilizing these versions.
The technical exploitation of this vulnerability occurs through a modified username authentication attack vector that allows an authenticated user to escalate their privileges within the end-user portal. When an attacker successfully logs in with manipulated credentials, they can traverse the system's access controls to view and manipulate any virtual machine within the portal interface regardless of their intended role permissions. This represents a fundamental breakdown in the principle of least privilege, where the system fails to properly validate user access rights against the resources they attempt to access. The vulnerability's impact extends beyond simple information disclosure to include full operational capabilities against virtual machines, as the attacker can perform any permitted operations on any virtual machine within the system's scope. This includes potentially destructive actions such as modifying virtual machine configurations, initiating shutdown operations, or accessing sensitive data stored within these virtual environments.
The operational implications of this vulnerability are severe and multifaceted, affecting both the confidentiality and integrity of virtualized infrastructure managed through UCS Director. Organizations utilizing affected versions face the risk of unauthorized access to critical virtual machine data, potentially exposing sensitive business information, intellectual property, or customer data stored within virtualized environments. The vulnerability's global configuration nature means that all virtual machines visible in the end-user portal become accessible to an attacker, eliminating any protection provided by individual virtual machine access controls. This creates a cascading security risk where a single compromised account can provide access to an entire virtual infrastructure, potentially affecting multiple business units or customer environments. The vulnerability directly maps to CWE-285 (Improper Authorization) and aligns with ATT&CK technique T1078 (Valid Accounts) and T1068 (Exploitation for Privilege Escalation), demonstrating how authentication bypasses can be leveraged to achieve unauthorized access to critical systems.
Organizations should implement immediate mitigations including applying the Cisco patch 3 release for UCS Director 6.0 and 6.5 versions to address the authentication validation flaw. System administrators must also conduct thorough access control reviews to ensure that user permissions are properly configured and that the principle of least privilege is enforced across all virtual machine management operations. Network segmentation and monitoring should be enhanced to detect unusual authentication patterns or unauthorized access attempts within the UCS Director environment. Additional defensive measures include implementing multi-factor authentication for privileged accounts, conducting regular security assessments of virtual infrastructure management systems, and establishing robust audit trails for all virtual machine operations. The vulnerability highlights the critical importance of proper access control implementation in virtualized environments and serves as a reminder of the potential damage that can result from inadequate authentication validation mechanisms in enterprise infrastructure management systems.