CVE-2023-28001 in FortiOS
Summary
by MITRE • 07/11/2023
An insufficient session expiration in Fortinet FortiOS 7.0.0 - 7.0.12 and 7.2.0 - 7.2.4 allows an attacker to execute unauthorized code or commands via reusing the session of a deleted user in the REST API.
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Analysis
by VulDB Data Team • 07/30/2023
The vulnerability identified as CVE-2023-28001 represents a critical session management flaw in Fortinet FortiOS versions 7.0.0 through 7.0.12 and 7.2.0 through 7.2.4. This weakness stems from insufficient session expiration mechanisms that fail to properly invalidate authentication tokens when users are deleted from the system. The vulnerability specifically affects the REST API interface, creating a persistent security gap that can be exploited by malicious actors. The flaw allows unauthorized code execution or command injection through the reuse of session identifiers from previously deleted user accounts, effectively bypassing authentication controls and enabling persistent access to sensitive system functions.
This vulnerability aligns with CWE-613, which addresses insufficient session expiration, and represents a direct violation of secure session management principles outlined in the OWASP Top Ten security framework. The technical implementation flaw occurs within the FortiOS REST API authentication subsystem where session tokens are not properly invalidated upon user deletion, creating a window of opportunity for attackers to leverage stale session identifiers. The attack vector requires minimal privileges initially, as the attacker can exploit the existing session tokens without needing to perform additional authentication steps. The vulnerability is particularly concerning because it operates at the application layer, targeting the authentication and authorization mechanisms that form the foundation of system security controls.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass potential full system compromise and data exfiltration. An attacker exploiting this vulnerability could execute arbitrary commands on the FortiOS device, potentially leading to complete network infrastructure compromise. The implications are severe given that FortiOS devices often serve as critical network security appliances including firewalls, VPN gateways, and intrusion prevention systems. The vulnerability enables persistent access that could remain undetected for extended periods, as the reused sessions maintain valid authentication state without proper expiration mechanisms. This creates a significant risk for organizations relying on FortiOS for network security, as the compromised device could become a persistent threat vector within the network infrastructure.
Organizations should implement immediate mitigations including upgrading to FortiOS versions that address this vulnerability, which typically involves patching to versions 7.0.13, 7.2.5, or later releases. Network administrators should also consider implementing additional monitoring for suspicious API access patterns and session reuse activities. The mitigation strategy should include comprehensive session management policies that enforce proper token invalidation upon user deletion and implement automatic session timeout mechanisms. Security teams should conduct thorough vulnerability assessments of their FortiOS deployments to identify any systems running affected versions and ensure all administrative access points are secured. Additionally, organizations should implement network segmentation and access controls to limit the potential impact of any successful exploitation, as the vulnerability could enable attackers to move laterally within the network infrastructure. The remediation process must include verification that session tokens are properly invalidated and that no stale sessions remain active after user account deletion, addressing the root cause of the vulnerability through proper implementation of secure session management practices.