FortiBleed is an ongoing global campaign targeting internet-facing Fortinet FortiGate firewalls and SSL VPN gateways. It exploits reused or leaked credentials and legacy SHA-256 password storage to harvest and crack authentication data at scale. Attackers gain access by scanning for exposed SSL VPN portals, performing credential stuffing and password spraying, and cracking stolen password hashes offline. Once inside, they create new administrative accounts for persistence and conduct Active Directory enumeration to expand access. Organizations may experience account lockouts due to attacker actions. The campaign acts as an initial-access broker with links to ransomware affiliates INC/Lynx and Payload, representing a significant medium-severity threat requiring immediate defensive measures.
An exposed attacker server has unveiled FortiBleed, a large-scale credential-compromise campaign targeting internet-facing Fortinet FortiGate firewalls and SSL VPN gateways globally. This operation involved credential harvesting through reuse, brute force, and hash cracking using a distributed GPU infrastructure with approximately 36 rented GPUs via Hashtopolis. The exposed directory contained 319 files revealing scanning tools, cracking infrastructure, credential databases, post-exploitation toolkits, and active VPN configurations. While initially reported as affecting 21,632 domains, analysis of the attacker's own tooling reveals only 918 organizations showed evidence of internal network compromise, with merely 148 confirmed cases where credentials were fully cracked. The operation ultimately aimed to sell initial access to compromised networks, with victims spanning 194 countries, predominantly India, United States, and Taiwan.
A significant spike in brute-force traffic targeting Fortinet SSL VPNs was observed on August 3, with over 780 unique IPs triggering the Fortinet SSL VPN Bruteforcer tag. The activity was deliberate and precise, focusing on FortiOS. Two distinct waves of attacks were identified: a long-running set of brute-force activity and a sudden burst beginning August 5. The second wave shifted from targeting FortiOS to FortiManager - FGFM profile. Historical data revealed a potential residential origin or proxy use. The analysis suggests evolving attack patterns and potential reuse of tooling. Research indicates that such spikes often precede new vulnerability disclosures within six weeks. Defenders are advised to use GreyNoise to search for and block malicious IPs associated with this campaign.
UMBRELLA STAND is a sophisticated malware targeting FortiGate 100D series firewalls produced by Fortinet. It contains remote shell execution functionality, configurable beacon frequency, and AES-encrypted C2 communications. The malware uses fake TLS on port 443 to beacon to its C2 server and has the ability to run shell commands. It employs various defense evasion techniques such as hidden folders, generic filenames, and string encryption. UMBRELLA STAND also has persistence mechanisms through reboot hooking and ldpreload. Associated tooling includes BusyBox, nbtscan, tcpdump, and openLDAP. The malware demonstrates operational security considerations and shares similarities with previously reported COATHANGER malware.
