CVE-2018-13382 in FortiOS
Summary
by MITRE
An Improper Authorization vulnerability in Fortinet FortiOS 6.0.0 to 6.0.4, 5.6.0 to 5.6.8 and 5.4.1 to 5.4.10 under SSL VPN web portal allows an unauthenticated attacker to modify the password of an SSL VPN web portal user via specially crafted HTTP requests.
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Analysis
by VulDB Data Team • 09/09/2024
The vulnerability identified as CVE-2018-13382 represents a critical improper authorization flaw within Fortinet FortiOS SSL VPN web portal functionality. This weakness affects multiple versions of the FortiOS operating system including 6.0.0 through 6.0.4, 5.6.0 through 5.6.8, and 5.4.1 through 5.4.10, creating a widespread exposure across the Fortinet security platform ecosystem. The vulnerability specifically targets the SSL VPN web portal component, which serves as a critical access point for remote users to connect to corporate networks through secure SSL connections. The flaw allows an unauthenticated attacker to exploit a lack of proper access controls during password modification operations, effectively bypassing the normal authentication requirements that should protect user account management functions.
The technical implementation of this vulnerability stems from insufficient input validation and authorization checks within the SSL VPN web portal's password change functionality. Attackers can craft specially designed HTTP requests that manipulate the authentication flow to modify user passwords without providing valid credentials or session tokens. This improper authorization condition falls under the CWE-285 category of "Improper Authorization" and specifically relates to the failure to properly validate that the requesting entity has the necessary permissions to perform administrative operations. The vulnerability exploits the trust placed in certain HTTP parameters or headers that should normally be validated against authenticated user sessions, allowing attackers to inject malicious payloads that bypass normal security controls.
The operational impact of this vulnerability extends beyond simple credential compromise, as it enables attackers to gain persistent access to SSL VPN portals and potentially escalate privileges within the compromised network. An attacker who successfully exploits this vulnerability can modify any SSL VPN user account password, effectively locking out legitimate users while simultaneously gaining unauthorized access to corporate resources. This creates a significant risk for organizations that rely heavily on SSL VPN connectivity for remote access, as the attack requires no prior authentication credentials and can be executed remotely over the network. The vulnerability directly impacts the confidentiality, integrity, and availability of the SSL VPN service, potentially leading to unauthorized network access, data exfiltration, and lateral movement within the compromised environment.
Organizations affected by this vulnerability should immediately implement mitigations including applying the latest Fortinet firmware updates that address the authorization flaw, implementing network segmentation to limit access to SSL VPN services, and conducting thorough security audits of SSL VPN configurations. The ATT&CK framework categorizes this type of vulnerability under T1078 Valid Accounts and T1566 Phishing, as attackers can leverage compromised SSL VPN accounts to establish persistent access and potentially escalate privileges through additional attacks. Security teams should also consider implementing web application firewalls to detect and block suspicious HTTP request patterns, monitoring for unusual authentication attempts, and conducting regular penetration testing to identify similar authorization flaws within the SSL VPN infrastructure. The vulnerability highlights the critical importance of proper input validation and authentication checks in web applications, particularly those handling sensitive user account management functions.