CVE-2018-6436 in Fabric OS
Summary
by MITRE
A Vulnerability in the firmwaredownload command of Brocade Fabric OS command line interface (CLI) versions before 8.2.1, 8.1.2f, 8.0.2f, 7.4.2d could allow a local attacker to escape the restricted shell and, gain root access.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 04/11/2020
The vulnerability identified as CVE-2018-6436 represents a critical privilege escalation flaw within the Brocade Fabric OS command line interface that affects multiple version branches including 8.2.1, 8.1.2f, 8.0.2f, and 7.4.2d. This vulnerability specifically targets the firmware download command functionality within the restricted shell environment, creating a pathway for local attackers to bypass security controls and achieve elevated privileges. The issue stems from inadequate input validation and improper privilege handling within the CLI subsystem, allowing malicious actors to exploit command execution flows that should remain restricted to authorized users only.
The technical flaw manifests through improper sanitization of command parameters during firmware download operations, where the system fails to properly validate user inputs before executing privileged operations. This vulnerability operates at the intersection of CWE-20, which addresses improper input validation, and CWE-264, concerning permissions, privileges, and access controls. The restricted shell environment designed to limit user capabilities becomes compromised when the firmware download command processes specific input sequences that trigger unintended code execution paths, ultimately leading to root access escalation. Attackers can leverage this flaw by crafting malicious command inputs that exploit the underlying parsing mechanism to escape the restricted environment and gain full system privileges.
From an operational impact perspective, this vulnerability presents a severe threat to network infrastructure security as it allows local attackers with basic user privileges to escalate to root access without requiring additional authentication or external attack vectors. The implications extend beyond simple privilege escalation since Brocade Fabric OS serves as critical network infrastructure for storage area networks, making this vulnerability particularly dangerous for enterprise environments. Organizations utilizing affected Brocade switches face potential data breaches, unauthorized network modifications, and complete system compromise. The vulnerability affects network security operations by undermining the fundamental security model of restricted user environments and could enable attackers to establish persistent access points within network infrastructure.
Mitigation strategies for CVE-2018-6436 should prioritize immediate patch deployment across all affected Brocade Fabric OS versions, with particular attention to the specific version releases mentioned in the vulnerability description. System administrators should implement network segmentation and access controls to limit local user access to affected systems, while monitoring for suspicious command execution patterns. The vulnerability aligns with ATT&CK technique T1068, which covers local privilege escalation, and T1566, addressing malicious command execution. Organizations should also consider implementing additional logging and monitoring of CLI command activities, particularly around firmware download operations, to detect potential exploitation attempts. Regular security assessments of network infrastructure components and maintaining updated security patches remain essential defensive measures against similar vulnerabilities in network device management interfaces.