This one was devious. The instructor explained: "A firewall can be in front of a host, but the host's own IP stack has a Time-To-Live. If you set your TTL to expire one hop after the firewall but before the target’s IDS , your malicious packet reaches the host, but the host's response never makes it back to the firewall's state table. Asymmetric routing. The firewall forgets you exist."
Maya blinked. "Wait—I didn't use fake credentials. I used DNS tunneling and TTL evasions." This one was devious
The instructor’s tone hardened. "Firewalls are not walls. They are filters. And filters have assumptions." Asymmetric routing
The clock on the wall of Lab 4B read 11:47 PM. For most people, that meant sleep. For Maya Chen, a junior penetration tester at Syphon Security, it meant the course had finally gone live. I used DNS tunneling and TTL evasions