Fortinet SSL VPNs Hit by Global Brute-Force Wave Before Attackers Shift to FortiManager
Aug 12, 2025
Threat Intelligence / Enterprise Security
Cybersecurity researchers are warning of a "significant spike" in brute-force traffic aimed at Fortinet SSL VPN devices. The coordinated activity, per threat intelligence firm GreyNoise, was observed on August 3, 2025, with over 780 unique IP addresses participating in the effort. As many as 56 unique IP addresses have been detected over the past 24 hours. All the IP addresses have been classified as malicious, with the IPs originating from the United States, Canada, Russia, and the Netherlands. Targets of the brute-force activity include the United States, Hong Kong, Brazil, Spain, and Japan. "Critically, the observed traffic was also targeting our FortiOS profile, suggesting deliberate and precise targeting of Fortinet's SSL VPNs," GreyNoise said . "This was not opportunistic -- it was focused activity." The company also pointed out that it identified two distinct assault waves spotted before and after August 5: One, a long-running, brute-force a...