Unveiling the Vulnerability: Researchers Create Exploit Code for Critical Fortinet VPN Bug

Exploit Code for Critical Fortinet VPN Vulnerability Highlights Internet Security Concerns

Introduction

Researchers at Bishop Fox have developed exploit code for a critical remote code execution (RCE) vulnerability in Fortinet‘s FortiGate SSL VPNs. Despite Fortinet disclosing and patching the flaw in June 2023, an estimated 340,000 unpatched devices remain vulnerable to attack. The severity of the situation is underscored by the fact that this number is higher than originally estimated. The vulnerability, tracked as CVE-2023-27997, allows an unauthenticated, remote attacker to execute arbitrary code on affected devices and gain complete control. Given the potential scale of exploitation, this issue raises serious concerns about internet security and the need for prompt action.

The Scope of the Vulnerability

After discovering the vulnerability, French cybersecurity firm Lexfo assessed that it affects every Fortinet SSL VPN appliance running FortiOS. Additionally, Bishop Fox’s research indicates that approximately 69% of the 490,000 affected FortiGate SSL VPN interfaces exposed on the internet remain unpatched. These findings highlight the urgent need for organizations to patch their affected devices promptly.

Risk of Exploitation and Potential Threat Actors

The availability of exploit code for the Fortinet VPN vulnerability raises concerns over the potential for unauthorized individuals or threat actors to take advantage of it. Fortinet itself has cautioned about the potential for threat actors like those behind the Volt Typhoon cyber-espionage campaign to abuse this vulnerability. The Volt Typhoon group, believed to be based in China, has exploited other Fortinet vulnerabilities in the past to gain persistent access to critical infrastructure networks for malicious purposes, such as data theft.

Why Security Appliances are High-Value Targets

Fortinet‘s appliances, along with those of other firewall and VPN vendors, are attractive targets for adversaries due to the significant access they provide to enterprise networks. The high volume of critical Fortinet vulnerabilities that have been exposed illustrates the constant threat landscape that organizations face. In recent years, multiple advisory organizations, including the US Cybersecurity and Infrastructure Security Agency (CISA) and the National Security Agency (NSA), have highlighted the need for organizations to promptly address vulnerabilities in network devices due to the high level of attacker interest.

Recommendations for Organizations

The consequences of leaving critical vulnerabilities unpatched can be severe, as highlighted by the Bishop Fox research. Organizations must prioritize the prompt patching of vulnerable Fortinet devices to mitigate the risk of exploitation.

Patching Appliances

While patching firmware on appliances comes with its own challenges, it is an essential step to ensure network security. Timothy Morris, Chief Security Adviser at Tanium, advises that configuration backups should be made before patching and restored to verify that they are working as expected. This process may require some downtime and potentially involves risks, but organizations must prioritize security over convenience.

Conclusion

The development of exploit code for a critical Fortinet VPN vulnerability and the large number of unpatched devices highlight the ongoing challenges organizations face in maintaining internet security. Prompt patching and proactive measures are essential to mitigate the risk of exploitation by threat actors. By taking these steps, organizations can protect their networks and sensitive data from potential compromise. The Fortinet case serves as a reminder that constant vigilance and timely response are critical in the current cybersecurity landscape.