The Silent Threat: Old FortiGate Vulnerability Bypasses 2FA

The cybersecurity landscape is a constant struggle between innovation and exploitation. While new vulnerabilities emerge daily, sometimes the most dangerous threats are those we thought were long behind us. Such is the case with a Fortinet FortiGate flaw, specifically FG-IR-19-283 (CVE-2020-12812), which, despite being patched in July 2020, is now being actively exploited by cybercriminals to bypass two-factor authentication (2FA) on firewalls. This concerning development highlights the critical importance of continuous vigilance and robust patch management for organizations relying on FortiGate devices.

Understanding FG-IR-19-283 (CVE-2020-12812): A Persistent Weakness

At its core, CVE-2020-12812 is an authentication bypass vulnerability affecting Fortinet FortiGate firewalls. This flaw, first identified three years ago, allows attackers to sidestep standard authentication mechanisms, including 2FA. The critical aspect of its current exploitation is its ability to grant unauthorized access to crucial network components, such as VPNs and administrative consoles. This level of access can lead to significant data breaches, network disruption, and complete compromise of an organization’s infrastructure.

Active Exploitation: Cybercriminals Bypassing 2FA

Fortinet’s Product Security Incident Response Team (PSIRT) recently issued a stark warning, detailing in-the-wild attacks leveraging this specific vulnerability. This is not a theoretical threat; it’s an active campaign where cybercriminals are successfully exploiting the flaw to gain illicit access. The ability to bypass 2FA is particularly alarming, as multi-factor authentication is widely considered a cornerstone of modern cybersecurity defenses. Its circumvention means that even organizations with seemingly strong security postures may be vulnerable if their FortiGate firewalls remain unpatched or improperly configured.

The Impact: What Unauthorized Access Means

Gaining unauthorized access to FortiGate firewalls through this vulnerability opens the door to a myriad of malicious activities. Attackers could:

• Tunnel into Internal Networks: Utilize compromised VPN connections to move laterally within an organization’s private network.
• Exfiltrate Sensitive Data: Access and steal confidential information, intellectual property, or customer data.
• Deploy Malware and Ransomware: Inject malicious software, leading to system outages and potential extortion attempts.
• Manipulate Network Configurations: Alter firewall rules, create new backdoors, or disrupt critical services.
• Establish Persistence: Maintain long-term access to the network for future attacks.

Remediation Actions: Securing Your FortiGate Infrastructure

Given the severity and active exploitation of CVE-2020-12812, immediate action is crucial for all organizations utilizing FortiGate firewalls. Fortinet’s PSIRT team strongly urges administrators to:

• Immediate Patching: Ensure all FortiGate devices are updated to the latest firmware versions that address CVE-2020-12812. This is the most critical step. Consult Fortinet’s official advisories for specific patch levels.
• Configuration Audit: Conduct a thorough audit of all FortiGate configurations, particularly focusing on authentication settings, VPN access policies, and administrative interfaces. Verify that no unauthorized changes have been made.
• Review Logs: Scrutinize FortiGate logs for any suspicious login attempts, atypical traffic patterns, or unauthorized access events, especially from older timeframes if the vulnerability was present.
• Strengthen Access Controls: Implement the principle of least privilege for all administrative accounts. Regularly review and revoke unnecessary access.
• Network Segmentation: Implement strong network segmentation to limit the lateral movement of attackers if a firewall is compromised.
• External Vulnerability Scanning: Regularly perform external vulnerability scans to identify any unpatched systems or exposed services.

Tools for Detection and Mitigation

Leveraging appropriate tools can significantly aid in identifying and addressing potential exposures related to this FortiGate vulnerability.

Tool Name	Purpose	Link
FortiAnalyzer	Centralized logging and analysis for Fortinet devices, aiding in anomaly detection.	Fortinet FortiAnalyzer
Nessus	Vulnerability scanner capable of detecting CVE-2020-12812 and other vulnerabilities.	Tenable Nessus
OpenVAS	Open-source vulnerability scanner for comprehensive network assessments.	OpenVAS
FortiGuard Labs Updates	Provides up-to-date threat intelligence and security advisories from Fortinet.	FortiGuard Threat Intelligence

Conclusion: The Enduring Challenge of Patch Management

The active exploitation of a three-year-old FortiGate vulnerability serves as a stark reminder that simply patching a flaw once is not enough. Continuous monitoring, diligent patch management verification, and proactive security audits are essential to mitigate risks. Organizations must prioritize immediate action to secure their FortiGate firewalls against CVE-2020-12812 and related threats, ensuring the integrity of their network defenses and the safety of their data.