CVE-2018-6440 in Fabric OS
Summary
by MITRE
A vulnerability in the proxy service of Brocade Fabric OS versions before 8.2.1, 8.1.2f, 8.0.2f, 7.4.2d could allow remote unauthenticated attackers to obtain sensitive information and possibly cause a denial of service attack.
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Analysis
by VulDB Data Team • 04/17/2020
The vulnerability identified as CVE-2018-6440 represents a critical information disclosure flaw within the proxy service component of Brocade Fabric OS software across multiple affected versions. This vulnerability specifically impacts the fabric switch operating system that manages storage area network infrastructure, making it particularly concerning for enterprise environments that rely heavily on SAN connectivity. The flaw exists within the proxy service implementation which handles various network communication protocols and management functions, creating an attack surface that remote unauthenticated adversaries can exploit without requiring any credentials or prior access to the system. The vulnerability was discovered in versions prior to 8.2.1, 8.1.2f, 8.0.2f, and 7.4.2d, indicating a widespread issue affecting multiple release branches of the Fabric OS software.
The technical nature of this vulnerability stems from improper access controls and insufficient input validation within the proxy service functionality. Attackers can leverage this weakness to perform unauthorized data retrieval operations that expose sensitive system information including configuration details, network topology data, and potentially authentication credentials or session tokens. The flaw operates at the network protocol level where the proxy service processes incoming requests, failing to properly validate or restrict access to internal system resources. This type of vulnerability maps directly to CWE-200, which describes improper exposure of sensitive information, and represents a classic example of insufficient access control mechanisms. The proxy service in question likely handles various management protocols such as SNMP, HTTP, or other administrative interfaces that are commonly used for fabric management and monitoring.
The operational impact of CVE-2018-6440 extends beyond simple information disclosure to potentially enable more severe attacks including denial of service conditions. When attackers can access internal system information, they gain valuable intelligence that can be used to plan further attacks or exploit other vulnerabilities within the same network infrastructure. The ability to cause denial of service through this vulnerability means that attackers could potentially disrupt critical storage network operations, leading to service interruptions that impact business continuity and data availability. Organizations with large SAN environments using affected Brocade switches face significant risk as this vulnerability could allow attackers to map the entire storage network topology, identify critical assets, and potentially escalate privileges through additional exploitation attempts. The remote nature of the attack means that threat actors can target these systems from outside the network perimeter, making traditional network-based security controls less effective against this specific threat vector.
Mitigation strategies for CVE-2018-6440 primarily focus on upgrading to patched versions of Brocade Fabric OS where the vulnerability has been addressed through proper access control implementations and input validation improvements. Organizations should prioritize immediate deployment of the vendor-provided security patches for all affected switch models and versions. Network segmentation and firewall rules should be implemented to restrict access to proxy service ports and management interfaces, although this approach provides only partial protection given the unauthenticated nature of the attack. Additional monitoring should be deployed to detect unusual access patterns or data retrieval attempts that might indicate exploitation attempts. Security teams should also conduct comprehensive vulnerability assessments of their SAN infrastructure to identify any other potential weaknesses that could be exploited in conjunction with this vulnerability. The remediation process should include thorough testing of patches in non-production environments before deployment to ensure operational stability and avoid unintended service disruptions in critical network infrastructure components.