The KRVTZ-NET IDS alerts from 2026-02-28 report network activity indicative of reconnaissance targeting Fortinet Fortigate VPN devices. The specific indicator is repeated GET requests to the /remote/logincheck endpoint, which is associated with CVE-2023-27997, a known vulnerability in Fortigate VPN appliances. This vulnerability allows unauthenticated attackers to potentially bypass authentication or execute unauthorized actions via crafted requests. The alerts originate from an IPv6 address (2001:470:1:c84::14) flagged by Emerging Threats (ET) as exploit attempts. Although no active exploits are currently confirmed in the wild and no patches are available, the activity suggests ongoing scanning or probing by threat actors seeking vulnerable Fortigate VPN devices. The reconnaissance phase is critical in the cyber kill chain as it precedes exploitation attempts. The lack of authentication requirement and automated nature of the scanning increase the risk of widespread probing. Fortigate VPNs are widely used globally for secure remote access, making them attractive targets. The low severity rating reflects the current absence of active exploitation and mitigations in place but does not diminish the importance of monitoring and preparedness. The technical details include a unique UUID and timestamp for tracking. The threat is categorized under OSINT and network activity, emphasizing its reconnaissance and observation nature rather than confirmed compromise.

If successfully exploited, CVE-2023-27997 could allow attackers to bypass authentication mechanisms on Fortigate VPN devices, potentially granting unauthorized access to internal networks. This could lead to data breaches, lateral movement within networks, and disruption of secure remote access services. Organizations relying on Fortigate VPNs for critical infrastructure, government communications, or enterprise remote access could face confidentiality and integrity risks. Although no active exploitation is currently observed, the reconnaissance activity indicates potential future attempts. The widespread deployment of Fortigate VPNs globally means a large attack surface exists, increasing the likelihood of targeted attacks in the future. The impact could be severe if attackers move beyond reconnaissance to exploitation, especially in sectors with sensitive data or critical operations. The low current severity suggests limited immediate impact, but the potential for escalation remains if vulnerabilities are exploited. The absence of patches complicates mitigation, increasing reliance on detection and network-level defenses. Overall, the threat poses a moderate risk with potential for high impact if exploitation occurs.

Organizations should implement enhanced monitoring of Fortigate VPN endpoints, focusing on unusual or repeated GET requests to /remote/logincheck. Deploying network intrusion detection/prevention systems (IDS/IPS) with updated signatures to detect CVE-2023-27997-related activity is critical. Network segmentation should isolate VPN devices from sensitive internal resources to limit lateral movement if compromised. Employ strict access controls and multi-factor authentication (MFA) on VPN devices to reduce risk even if authentication bypass is attempted. Fortinet customers should engage with Fortinet support and security advisories for any forthcoming patches or workarounds. Rate limiting and blocking suspicious IP addresses, especially those exhibiting scanning behavior like the identified IPv6 address, can reduce exposure. Regularly review VPN logs for anomalous access patterns and conduct penetration testing to assess Fortigate VPN security posture. Consider deploying web application firewalls (WAF) or reverse proxies to filter malicious requests targeting VPN portals. Finally, maintain up-to-date threat intelligence feeds to stay informed of evolving exploitation attempts related to this vulnerability.