The KRVTZ-NET IDS alerts dated 2026-02-23 highlight network reconnaissance activities detected by intrusion detection systems. The primary technical detail involves multiple IP addresses performing repeated GET requests to the /remote/logincheck endpoint on Fortigate VPN devices, which is associated with CVE-2023-27997, a known vulnerability allowing unauthenticated attackers to bypass authentication and potentially execute arbitrary commands. These repeated requests suggest scanning or exploitation attempts targeting this vulnerability. Additional indicators include inbound requests to hidden environment files and access attempts to web server PHP info pages, which are common reconnaissance techniques used to gather sensitive configuration information. The alerts are categorized as low severity and reconnaissance phase of the kill chain, with no patches available or known exploits actively used in the wild at the time of reporting. The lack of confirmed exploitation and ransomware use indicates this is primarily an observation of scanning activity rather than an active attack campaign. The presence of IPv6 and IPv4 addresses from diverse sources indicates a broad scanning effort. The technical details do not specify affected versions or direct impact, but the association with CVE-2023-27997 highlights the importance of securing Fortigate VPN endpoints. The feed is sourced from CIRCL OSINT and tagged for automated unsupervised processing, emphasizing the need for continuous monitoring and threat intelligence integration.

The potential impact of this threat is primarily related to reconnaissance and scanning activities that precede more serious exploitation attempts. If attackers successfully exploit CVE-2023-27997 on Fortigate VPN devices, they could bypass authentication controls, leading to unauthorized access, data exfiltration, or further network compromise. This could affect confidentiality, integrity, and availability of critical network infrastructure. Organizations relying on Fortigate VPNs for remote access are at risk of unauthorized access if they have not applied patches or mitigations. The reconnaissance activity also exposes organizations to targeted attacks by revealing system configurations and vulnerabilities. While no active exploits or ransomware campaigns are currently linked to these alerts, the presence of scanning activity indicates potential preparation for future attacks. The impact is mitigated by the current low severity and absence of known exploits in the wild, but the risk remains significant for unpatched systems. The broad geographic distribution of scanning IPs suggests a global threat landscape, with higher risk in countries with extensive Fortigate VPN deployments and critical infrastructure reliant on these devices.

1. Immediately verify and apply all available patches and firmware updates for Fortigate VPN devices to remediate CVE-2023-27997. 2. Implement strict access controls and network segmentation to limit exposure of VPN management interfaces to the internet. 3. Deploy and tune intrusion detection and prevention systems to detect and block repeated unauthorized requests to /remote/logincheck and other suspicious endpoints. 4. Monitor VPN logs for unusual authentication attempts or repeated login failures indicative of brute force or exploitation attempts. 5. Restrict access to sensitive web server files such as environment configuration files and phpinfo pages by enforcing least privilege and disabling unnecessary services. 6. Employ multi-factor authentication (MFA) on VPN access to reduce risk from credential compromise. 7. Conduct regular vulnerability assessments and penetration testing focused on VPN infrastructure. 8. Integrate threat intelligence feeds like CIRCL OSINT into security monitoring to stay informed of emerging reconnaissance and exploitation trends. 9. Educate network and security teams on the specific indicators of compromise related to CVE-2023-27997 and reconnaissance activity to improve incident response readiness.