FortiGate NGFW Exploitation: How Threat Actors Breach Networks via Service Account Credentials
Threat actors are actively targeting Fortinet FortiGate next-generation firewalls (NGFWs) to gain initial access into enterprise networks. Recent campaigns leverage authentication bypass vulnerabilities affecting FortiCloud Single Sign-On (SSO) functionality, allowing attackers to obtain administrative access to exposed devices. Once access is obtained, attackers are able to export the device configuration, gaining visibility into network architecture, firewall policies, and authentication integrations such as Active Directory or LDAP. This intelligence can be used to pivot deeper into internal networks. Organisations operating internet-accessible FortiGate appliances should review exposure and apply mitigations immediately. Vulnerabilities Observed The following vulnerabilities have been associated with active exploitation activity: • CVE-2025-59718 - FortiCloud SSO authentication bypass• CVE-2025-59719 - FortiCloud SSO authentication bypass• CVE-2026-24858 - Additional authentication bypass affecting SSO mechanisms These vulnerabilities may allow attackers to authenticate to the FortiGate administrative interface without valid credentials. Observed Attack Behaviour SOC investigations and threat-intelligence reporting indicate a consistent attack pattern:…
