CVE-2020-15376 in Fabric OS
Summary
by MITRE • 12/12/2020
Brocade Fabric OS versions before v9.0.0 and after version v8.1.0, configured in Virtual Fabric mode contain a weakness in the ldap implementation that could allow a remote ldap user to login in the Brocade Fibre Channel SAN switch with "user" privileges if it is not associated with any groups.
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Analysis
by VulDB Data Team • 12/16/2020
This vulnerability exists within Brocade Fabric OS software versions prior to v9.0.0 and following v8.1.0 when operating in Virtual Fabric mode. The weakness specifically resides in the Lightweight Directory Access Protocol implementation which fails to properly validate authentication requests from LDAP users. The flaw allows remote attackers to authenticate to the Fibre Channel SAN switch with only user-level privileges even when they are not associated with any administrative groups. This represents a significant security oversight in the authentication mechanism that could be exploited by unauthorized individuals to gain access to network resources. The vulnerability affects the core authentication infrastructure of the storage area network switch, potentially enabling attackers to perform unauthorized operations within the fabric environment.
The technical implementation flaw stems from insufficient input validation and authentication checking within the LDAP integration component of the Brocade Fabric OS. When LDAP users attempt authentication, the system does not properly verify whether the user has appropriate group memberships or access controls before granting basic user privileges. This misconfiguration allows any valid LDAP user to establish a session with the switch regardless of their intended access level. The vulnerability is particularly concerning because it operates at the authentication layer where proper access controls should be enforced. The flaw is classified as a weak authentication mechanism that violates fundamental security principles and could be leveraged to escalate privileges or conduct unauthorized operations within the SAN environment.
The operational impact of this vulnerability extends beyond simple unauthorized access to include potential data exposure and network disruption within the Fibre Channel SAN infrastructure. An attacker who successfully exploits this vulnerability can establish a persistent presence on the switch with user-level privileges, potentially enabling them to monitor network traffic, modify configurations, or disrupt services. The Virtual Fabric mode configuration amplifies the risk because it allows multiple virtual fabrics to coexist on a single physical switch, meaning that successful exploitation could affect multiple logical network segments. This vulnerability directly impacts the security posture of enterprise storage networks and could lead to compliance violations, data breaches, or service interruptions that affect critical business operations.
Organizations should immediately upgrade to Brocade Fabric OS version 9.0.0 or later to remediate this vulnerability, as this represents the official fix provided by the vendor. Additionally, network administrators should implement network segmentation and access controls to limit the exposure of vulnerable switches within the SAN environment. The implementation of additional authentication mechanisms such as two-factor authentication or certificate-based authentication can provide layered protection against unauthorized access attempts. Security monitoring should be enhanced to detect unusual authentication patterns or unauthorized access attempts to the switch management interfaces. Regular security assessments and vulnerability scanning should be conducted to identify any remaining instances of the vulnerable software versions within the organization's infrastructure. This vulnerability aligns with CWE-287 which addresses improper authentication issues and could be mapped to ATT&CK technique T1078 for valid accounts and T1566 for social engineering attacks that leverage weak authentication mechanisms.