Hackers Are Now Using Your Firewall To Break Into Your Network

The decision came from a senior security engineer at a mid-sized SaaS firm late last Thursday night. Faced with anomalous outbound traffic patterns from a core network device, they made the call to physically disconnect a critical FortiGate firewall, effectively taking a segment of their production environment offline. This drastic, costly move was the direct result of a threat intelligence report from SentinelOne, detailed by @TheHackersNews, which confirmed that their most trusted perimeter defense had likely been turned against them. Attackers are now systematically exploiting these ubiquitous appliances not just as targets, but as potent, credentialed launchpads for deeper network invasion.

Internal documents from cybersecurity response firms, shared with industry contacts, show the campaign leverages known but critical vulnerabilities in Fortinet’s SSL-VPN technology, particularly CVE-2024-21762. The objective is not simply to crash the firewall but to persistently compromise it, establishing a foothold that bypasses traditional security monitoring. Once inside the FortiGate, attackers can move laterally with the device’s own high-level permissions, accessing adjacent servers and workstations that would normally be considered secure. Engineers close to the project say the attackers’ sophistication lies in using the network’s own infrastructure—the very hardware bought to keep them out—as a camouflaged and powerful ally.

For any organization running these devices, the implication is severe. It transcends a standard software patch alert. A compromised firewall means every piece of data flowing through it could be intercepted, and every system behind it is potentially exposed. The integrity of the network perimeter itself is questioned. This isn’t a speculative threat; SentinelOne’s findings, as reported, indicate active, ongoing exploitation in the wild. The rollout of mitigations and patches by Fortinet has been anything but smooth, with some clients reporting configuration complexities that leave gaps even after updates are applied.

What happens next involves a painful and urgent audit for infrastructure teams globally. The immediate step is verifying that all FortiGate appliances, especially those exposing SSL-VPN, are running the latest firmware and that the specific critical vulnerabilities have been addressed—not just patched, but checked for indicators of compromise. The larger, uncertain timeline revolves around remediation for those already breached. If an attacker has owned a firewall for weeks, the scope of the incident grows exponentially. The industry is now watching for the first major breach disclosure directly attributed to this vector, which will reveal the full extent of the damage possible when your guard becomes the guide for the intruder.

Source: https://x.com/TheHackersNews/status/2031405324880769420