CVE-2016-8491 in FortiWLC
Summary
by MITRE
The presence of a hardcoded account named 'core' in Fortinet FortiWLC allows attackers to gain unauthorized read/write access via a remote shell.
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Analysis
by VulDB Data Team • 08/09/2020
The vulnerability identified as CVE-2016-8491 represents a critical security flaw in Fortinet FortiWLC wireless LAN controller appliances that stems from improper credential management practices. This issue manifests through the inclusion of a hardcoded administrative account named 'core' within the device firmware, which serves as a persistent backdoor mechanism accessible to unauthorized parties. The vulnerability specifically affects Fortinet FortiWLC products and demonstrates a fundamental failure in secure configuration management, where default credentials are embedded directly into the software rather than being dynamically generated or properly secured during deployment.
The technical implementation of this vulnerability involves a hardcoded username and password combination that remains static across all affected devices, creating an inherent security risk that persists regardless of network configuration changes or administrative password updates. Attackers can exploit this weakness by establishing a remote shell connection to the device using the predetermined credentials, which grants them full administrative privileges including read and write access to all system configurations, network policies, and potentially sensitive data stored within the wireless controller. This remote shell access capability enables attackers to manipulate wireless network settings, intercept communications, and potentially establish persistent access points within the network infrastructure.
The operational impact of CVE-2016-8491 extends beyond immediate unauthorized access to encompass broader network compromise and data exfiltration capabilities. Once attackers gain access through the hardcoded account, they can modify wireless access policies, create unauthorized user accounts, monitor network traffic, and potentially use the compromised device as a pivot point to attack other systems within the network perimeter. This vulnerability directly violates security best practices outlined in the OWASP Top Ten and aligns with CWE-798, which specifically addresses the use of hardcoded credentials in software applications. The persistent nature of hardcoded accounts makes this vulnerability particularly dangerous as it remains exploitable across multiple deployments and versions without requiring additional attack vectors.
Organizations affected by this vulnerability face significant risk exposure that can result in complete wireless network compromise and potential data breaches. The remote nature of the attack means that adversaries can exploit this flaw from anywhere on the internet without requiring physical access to the device or knowledge of the local network configuration. Mitigation strategies should include immediate firmware updates from Fortinet to address the hardcoded credential issue, implementation of network segmentation to limit lateral movement, and comprehensive network monitoring to detect unauthorized access attempts. Security teams must also conduct thorough inventory assessments to identify all affected FortiWLC devices and implement proper access controls including the use of strong, unique administrative credentials. This vulnerability demonstrates the critical importance of following the principle of least privilege and adheres to ATT&CK technique T1078 which covers legitimate credentials for persistence and defense evasion, making it essential for organizations to implement robust credential management policies and regular security assessments to prevent similar exposure scenarios.