Arctic Wolf warned of a new wave of automated attacks making unauthorized firewall configuration changes on Fortinet FortiGate devices.
Arctic Wolf researchers reported a new automated attack cluster observed since January 15, 2026, targeting FortiGate devices. Attackers created generic accounts for persistence, enabled VPN access, and exfiltrated firewall configurations. The activity resembles a December 2025 campaign involving admin SSO logins and config theft. Arctic Wolf has detections in place and is monitoring the evolving threat.
“Starting on January 15, 2026, Arctic Wolf began observing a new cluster of automated malicious activity involving unauthorized firewall configuration changes on FortiGate devices.” reads the report published by Arctic Wolf. “This activity involved the creation of generic accounts intended for persistence, configuration changes granting VPN access to those accounts, as well as exfiltration of firewall configurations. “
In December 2025, Fortinet disclosed two critical SSO authentication bypass flaws, tracked as CVE-2025-59718 and CVE-2025-59719, which are improper verification of cryptographic signature issues.
Threat actors started exploiting the two critical flaws in Fortinet products days after patch release, Arctic Wolf warned.
Arctic Wolf researchers observed attackers began exploiting critical Fortinet authentication bypass flaws on December 12, just three days after patches were issued. The attacks involved malicious SSO logins on FortiGate devices, mainly targeting admin accounts from multiple hosting providers. After gaining access, the attackers exported device configurations via the GUI. These files include hashed credentials, which threat actors can attempt to crack offline, increasing the risk of further compromise.
Recent intrusions show malicious SSO logins from a small set of hosting providers, often targeting the cloud-init@mail.io account. After successful SSO access, attackers quickly exported firewall configurations via the GUI and created secondary admin accounts for persistence. These actions occurred within seconds, suggesting highly automated activity.
The researchers published Indicators of Compromise (IoCs).
Follow me on Twitter: @securityaffairs and Facebook and Mastodon
(SecurityAffairs – hacking, Fortinet FortiGate)
