CVE-2016-4966 in FortiWan
Summary
by MITRE
The diagnosis_control.php page in Fortinet FortiWan (formerly AscernLink) before 4.2.5 allows remote authenticated users to download PCAP files via vectors related to the UserName GET parameter.
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Analysis
by VulDB Data Team • 11/01/2024
The vulnerability identified as CVE-2016-4966 affects Fortinet FortiWan appliances running firmware versions prior to 4.2.5, specifically targeting the diagnosis_control.php web interface page. This issue represents a critical access control flaw that enables remote authenticated attackers to exploit a weakness in the web application's parameter handling mechanism. The vulnerability manifests through the UserName GET parameter, which is improperly validated and sanitized within the diagnostic functionality of the appliance.
The technical flaw stems from insufficient input validation and access control enforcement within the web application layer of FortiWan devices. When an authenticated user submits a request containing a UserName GET parameter to the diagnosis_control.php page, the system fails to properly verify whether the requesting user has legitimate authorization to access PCAP files associated with other user accounts. This oversight creates a privilege escalation scenario where authenticated users can potentially access sensitive network traffic data belonging to other system users without proper authorization.
From an operational perspective, this vulnerability presents significant security implications for organizations relying on FortiWan appliances for network management and monitoring. The ability to download PCAP files remotely compromises network traffic confidentiality and can expose sensitive data such as usernames, passwords, and other network communications. The attack vector requires only authenticated access, making it particularly dangerous as it can be exploited by malicious insiders or compromised legitimate users. Network administrators may not immediately detect such unauthorized access attempts since the actions appear to originate from legitimate user accounts.
The vulnerability aligns with CWE-285, which addresses improper authorization issues in software systems, and represents a classic example of insufficient access control validation. From the MITRE ATT&CK framework perspective, this weakness maps to techniques involving privilege escalation and credential access, as attackers can leverage the authenticated session to gain access to data they should not be authorized to view. Organizations using FortiWan appliances should implement immediate mitigations including firmware updates to version 4.2.5 or later, which address the input validation issues and strengthen access controls around diagnostic functions. Additional protective measures include implementing network segmentation to limit access to diagnostic interfaces, enforcing strict authentication controls, and monitoring for unusual access patterns in system logs. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other network management components and ensure comprehensive protection against unauthorized data access.