TCP Fast Open - Bypass of stateless alerts
I have successfully verified that Suricata on latest release version v5.0.2 doesn't detect payloads using TFO (TCP Fast Open). Attached is a .pcap file with a directory path traversal payload which reads an /etc/passwd file, suricata rule to trigger alerts on packets which contain /etc/passwd payload so as the suricata.yaml configuration file.
- suricata -V
This is Suricata version 5.0.2 RELEASE
- suricata -c /etc/suricata/suricata.yaml -r tfo.pcap
This issue was addressed by Zeek in October, 2019.