CVE-2016-1909 in FortiOS
Summary
by MITRE
FortiOS 4.x before 4.3.17 and 5.0.x before 5.0.8 has a hardcoded passphrase for the Fortimanager_Access account, which allows remote attackers to obtain administrative access via an SSH session.
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Analysis
by VulDB Data Team • 09/01/2024
The vulnerability identified as CVE-2016-1909 represents a critical security flaw in Fortinet's FortiOS operating system affecting versions prior to specific patches. This issue resides within the authentication mechanism of the FortiOS platform and specifically targets the Fortimanager_Access account that is used for managing FortiManager connections. The vulnerability stems from a hardcoded passphrase that remains unchanged across different deployments, creating a persistent security weakness that can be exploited by unauthorized parties. This flaw is particularly concerning because it allows remote attackers to gain administrative privileges through standard SSH connections, bypassing normal authentication procedures.
The technical implementation of this vulnerability involves a hardcoded cryptographic key or passphrase that is embedded within the FortiOS firmware itself. This hardcoded credential mechanism violates fundamental security principles and aligns with CWE-798, which addresses the use of hard-coded credentials in software implementations. The Fortimanager_Access account serves as a bridge between FortiGate firewalls and FortiManager centralized management systems, making it a critical component for network administration. When attackers can exploit this hardcoded passphrase, they gain the ability to establish SSH sessions with administrative privileges, effectively providing them with full control over the affected FortiOS devices. This represents a privilege escalation vulnerability that can be exploited remotely without requiring any valid user credentials or prior access to the system.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to perform administrative functions such as modifying firewall rules, accessing sensitive network data, and potentially compromising entire network infrastructures. Attackers can leverage this vulnerability to conduct persistent threats, establish backdoors, or execute lateral movement within networks where FortiOS devices are deployed. The remote nature of the exploitation means that attackers do not need physical access or network proximity to the affected devices, making the vulnerability particularly dangerous for organizations with distributed network deployments. This vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under privilege escalation and remote access trojan tactics, where adversaries seek to maintain persistent access to target systems.
Organizations affected by this vulnerability should immediately implement remediation measures including applying the latest FortiOS patches released by Fortinet, specifically versions 4.3.17 and 5.0.8 or later. Network administrators should also consider implementing additional security controls such as SSH key-based authentication, network segmentation, and monitoring for unauthorized SSH connections. The vulnerability highlights the importance of proper credential management and the risks associated with embedded credentials in network infrastructure devices. Regular security assessments and vulnerability scanning should be conducted to identify similar hardcoded credentials in other network components, as this represents a common pattern in security vulnerabilities that can be exploited to gain unauthorized access to critical network infrastructure.