This threat report details IDS alerts capturing repeated GET requests to the /remote/logincheck endpoint on Fortigate VPN devices, associated with CVE-2023-27997. This vulnerability enables authentication bypass on vulnerable Fortigate VPN products. The observed activity is reconnaissance, part of the attack kill chain, signaling potential attempts to identify exploitable VPN infrastructure. Although no active exploitation or malware deployment is confirmed, the reconnaissance suggests increased risk. The alert is tagged low severity and does not include a CVSS score. Fortinet has issued official patches for this vulnerability, but this specific alert does not confirm patch application status. The IP address 2001:470:1:c84::30 is identified as the source of the suspicious requests.

If exploited, CVE-2023-27997 allows attackers to bypass authentication on Fortigate VPN devices, potentially granting unauthorized access to internal networks. This unauthorized access could lead to data breaches, lateral movement within corporate environments, and disruption of secure remote access services. The reconnaissance activity itself does not cause direct harm but indicates an increased risk of exploitation attempts. The low severity rating reflects the current observation status without confirmed exploitation or active compromise.

Fortinet has released official patches addressing CVE-2023-27997; organizations should ensure all Fortigate VPN devices are updated with these patches. Deploy and tune IDS/IPS solutions to detect and block repeated suspicious requests to the /remote/logincheck endpoint. Enforce multi-factor authentication on VPN access to reduce risk from credential bypass attempts. Implement network segmentation to limit VPN access to necessary resources. Monitor VPN logs and network traffic for unusual patterns indicative of reconnaissance or brute force attacks. Consider IP whitelisting or geo-fencing to reduce exposure to external scanning. Utilize threat intelligence feeds to stay informed about emerging exploits targeting Fortigate VPNs. Conduct regular vulnerability assessments and penetration testing focused on VPN infrastructure. The vendor manages remediation through official patches; no new patch status is indicated in this feed.