This rule is designed to detect traffic redirection on TCP ports, specifically in the context of a Bpfdoor exploit. Bpfdoor is a Linux backdoor that utilizes iptables to redirect incoming TCP traffic on port 22 (commonly used for SSH) to an alternative port controlled by the attacker. The nature of this redirection can mask malicious activity, as it disguises communication as legitimate SSH traffic, potentially bypassing conventional security measures. The detection looks for the execution of the `iptables` command, specifically checking for the `-t nat` table and any directives that indicate a redirection to alternate ports. The rule raises an alert if it finds such command execution that fits the outlined pattern, indicating possible evasion tactics being employed by attackers.