CVE-2021-32595 in FortiPortal
Summary
by MITRE • 11/02/2021
Multiple uncontrolled resource consumption vulnerabilities in the web interface of FortiPortal before 6.0.6 may allow a single low-privileged user to induce a denial of service via multiple HTTP requests.
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Analysis
by VulDB Data Team • 11/06/2021
The vulnerability identified as CVE-2021-32595 represents a critical resource consumption flaw within the web interface of FortiPortal appliances running versions prior to 6.0.6. This issue stems from inadequate input validation and resource management within the web server component, allowing malicious actors to exploit specific HTTP request patterns to exhaust system resources. The vulnerability specifically affects the authentication and session management mechanisms, creating a pathway for denial of service attacks that can severely impact network access control services. Organizations relying on FortiPortal for wireless access authentication and user management face significant operational risks when exposed to this vulnerability.
The technical exploitation of CVE-2021-32595 occurs through carefully crafted HTTP requests that trigger resource allocation without proper bounds checking. Attackers can leverage this flaw by sending multiple concurrent requests that consume memory, CPU cycles, and file descriptor resources at an accelerated rate. The vulnerability manifests as a failure to implement rate limiting or resource quotas within the web interface, enabling a single low-privileged user to perform sustained resource exhaustion attacks. This flaw aligns with CWE-400, which categorizes uncontrolled resource consumption as a common weakness leading to denial of service conditions. The implementation lacks proper defensive measures such as request throttling, connection limiting, and resource monitoring that would normally prevent such abuse scenarios.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the entire network access infrastructure managed by FortiPortal. When exploited successfully, the vulnerability can render the web interface unavailable, preventing legitimate users from accessing authentication services, managing wireless networks, or performing administrative tasks. This creates cascading effects throughout the organization's network security posture, as users may be unable to connect to wireless networks or access network resources through the compromised authentication system. The low privilege requirement means that even unauthenticated attackers can potentially exploit this vulnerability, making it particularly dangerous in environments where network access controls are critical for security operations.
Organizations should implement immediate mitigations including upgrading to FortiPortal version 6.0.6 or later, which contains patches addressing the resource consumption issues. Network administrators should also configure rate limiting rules at the firewall level to restrict the number of concurrent HTTP requests to the web interface. Additional defensive measures include implementing connection tracking limits, monitoring for unusual resource consumption patterns, and establishing automated alerting for potential exploitation attempts. The vulnerability demonstrates the importance of proper input validation and resource management in web applications, aligning with ATT&CK technique T1499.004 for network denial of service attacks. Organizations should also review their incident response procedures to ensure rapid detection and remediation of similar resource exhaustion vulnerabilities in other network infrastructure components.