CVE-2018-9185 in FortiOS
Summary
by MITRE
An information disclosure vulnerability in Fortinet FortiOS 6.0.0 and below versions reveals user's web portal login credentials in a Javascript file sent to client-side when pages bookmarked in web portal use the Single Sign-On feature.
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Analysis
by VulDB Data Team • 04/03/2023
The vulnerability identified as CVE-2018-9185 represents a critical information disclosure flaw within Fortinet FortiOS versions 6.0.0 and earlier, specifically affecting the web portal authentication mechanism. This weakness stems from improper handling of session data within the Single Sign-On implementation, where sensitive user credentials become inadvertently exposed through client-side javascript files. The vulnerability manifests when users access bookmarked pages within the web portal environment, creating a persistent exposure vector that can be exploited by malicious actors.
The technical root cause of this vulnerability lies in the improper sanitization and handling of authentication tokens within the javascript delivery mechanism. When Single Sign-On functionality is enabled and users navigate to bookmarked pages, the system fails to adequately strip or obfuscate sensitive credential information before transmitting javascript content to the browser. This creates a scenario where user login credentials, session identifiers, and potentially other authentication-related data become accessible through the javascript files that are cached or executed by the client-side browser environment. The flaw operates at the application layer and specifically targets the web portal interface components of the FortiOS operating system.
The operational impact of this vulnerability extends beyond simple credential exposure, as it fundamentally undermines the security posture of organizations relying on Fortinet's web portal authentication. Attackers can exploit this weakness to gain unauthorized access to user accounts, potentially leading to full system compromise through privilege escalation attacks. The exposure occurs without requiring any special authentication or network access, making it particularly dangerous as it can be exploited by anyone who can access the affected javascript files. This vulnerability directly violates security principles outlined in the OWASP Top Ten and aligns with CWE-200 (Information Exposure) and CWE-352 (Cross-Site Request Forgery) categories, creating a significant risk for organizations using vulnerable FortiOS versions.
Organizations should immediately implement mitigations including upgrading to Fortinet FortiOS 6.0.1 or later versions where this vulnerability has been addressed through proper credential sanitization and session management improvements. Network administrators must also review and implement proper access controls for web portal resources, ensuring that javascript files containing sensitive information are properly secured and that unnecessary caching of authentication-related content is disabled. The ATT&CK framework categorizes this vulnerability under T1566 (Phishing) and T1078 (Valid Accounts) as it enables adversaries to obtain valid credentials through information disclosure rather than traditional attack vectors. Additionally, implementing network segmentation, monitoring for unusual javascript file access patterns, and conducting regular security assessments of web portal components can help reduce the attack surface and prevent exploitation of this vulnerability.