The KRVTZ-NET IDS alerts dated 2026-02-15 highlight network reconnaissance activities focusing on Fortinet FortiOS VPN devices. Attackers are performing repeated GET requests to the /remote/logincheck endpoint, which is linked to CVE-2023-27997, a known vulnerability in Fortinet VPNs that allows unauthenticated remote probing of login functionality. This vulnerability can be exploited to gain unauthorized access or cause denial of service. The alerts include multiple IP addresses identified as sources of these exploit attempts, including IPv6 and IPv4 addresses, some associated with known scanning services like Censys and Google Webcrawler user agents. Additional reconnaissance techniques observed include requests to hidden environment files, which may expose sensitive configuration data if accessible. The activity is categorized as reconnaissance in the cyber kill chain, indicating early-stage attacker behavior aimed at gathering information before launching more severe attacks. No patches are explicitly noted as unavailable, but the report does not confirm patch status, emphasizing the need for organizations to verify and apply updates. No known active exploits or ransomware campaigns are currently associated with these alerts. The low severity rating reflects the reconnaissance nature rather than active exploitation, but the lack of authentication required for these probes increases risk. The technical details include a unique UUID and timestamp for correlation. Overall, this intelligence suggests persistent scanning of Fortinet VPN infrastructure, which is widely used in enterprise and government networks, particularly across Europe. This reconnaissance could precede exploitation attempts if vulnerabilities remain unmitigated.

The primary impact of this threat is the potential compromise of Fortinet FortiOS VPN devices if CVE-2023-27997 is successfully exploited. Fortinet VPNs are extensively deployed in Europe across private enterprises, government agencies, and critical infrastructure sectors. Successful exploitation could lead to unauthorized access to internal networks, data exfiltration, disruption of secure remote access services, and lateral movement within affected networks. The reconnaissance activity itself, while low severity, signals persistent attacker interest and increases the likelihood of future exploitation attempts. Requests to hidden environment files could expose sensitive configuration or credential information if improperly secured, further elevating risk. Disruption or compromise of VPN infrastructure can severely impact business continuity, confidentiality, and integrity of communications. Given the broad geographic distribution of scanning IPs and the strategic importance of VPNs for secure remote access, organizations must treat this as an early warning. The threat is particularly significant for countries with high Fortinet market penetration and critical infrastructure reliance on VPNs. Although no active exploits are currently observed, the reconnaissance phase often precedes more damaging attacks such as ransomware or data breaches, underscoring the need for proactive defense.

1. Immediately verify and apply all available Fortinet patches and firmware updates addressing CVE-2023-27997 and related vulnerabilities. 2. Restrict access to VPN management interfaces by implementing strict network segmentation and allowing connections only from trusted IP addresses or internal networks. 3. Deploy and fine-tune IDS/IPS solutions to detect and alert on repeated GET requests to /remote/logincheck and other suspicious VPN login activities. 4. Monitor VPN and network logs closely for unusual access patterns, especially from identified scanning IP addresses, and block or throttle suspicious sources at the firewall level. 5. Conduct regular vulnerability assessments and penetration testing focused on VPN infrastructure to proactively identify and remediate weaknesses. 6. Harden VPN configurations by enforcing multi-factor authentication, strong password policies, session limits, and disabling unnecessary services. 7. Secure access to environment and configuration files to prevent unauthorized exposure, including proper file permissions and web server configurations. 8. Educate security teams to recognize reconnaissance indicators and escalate incidents promptly for investigation. 9. Consider deploying web application firewalls (WAF) or reverse proxies to filter and block malicious HTTP requests targeting VPN endpoints. 10. Maintain collaboration with threat intelligence providers to stay updated on emerging threats and indicators related to Fortinet VPN exploitation attempts.