Tuesday, 26 February 2019

Venom - A Multi-hop Proxy For Penetration Testers

Venom is a multi-hop proxy tool developed for penetration testers using Go.

You can use venom to easily proxy network traffic to a multi-layer intranet, and easily manage intranet nodes.


  • network topology
  • multi-hop socks5 proxy
  • multi-hop port forward
  • port reuse (apache/mysql/...)
  • ssh tunnel
  • interactive shell
  • upload and download file
  • supports multiple platforms(Linux/Windows/MacOS) and multiple architectures(x86/x64/arm/mips)


You can directly download the executable files from https://github.com/Dliv3/Venom/releases

If you want to compile the project from source, you need to install go >= 1.11, then execute the following commands.

go get -u github.com/Dliv3/Venom/...

# $GOPATH is the environment variable configured when Go is installed. It can be viewed by the 'go env' command.
cd $GOPATH/src/github.com/Dliv3/Venom

# Compiled binary files are stored in the release folder in the current directory.


1. admin/agent command line parameters

  • Both the admin node and the agent node can act as a server or client.

Admin listens on the port 9999, the agent connects to the admin:

./admin_macos_x64 -lport 9999
./agent_linux_x64 -rhost -rport 9999

Agent listens on the port 8888, the admin connects to the agent:

./agent_linux_x64 -lport 8888
./admin_macos_x64 -rhost -rport 8888

  • The agent node supports port reuse.
Agent provides two port reuse methods
  1. Port reuse via SO_REUSEPORT and SO_REUSEADDR options
  2. Port reuse via iptables (Linux platform only)

The ports of most services can be reused on linux.

The ports of services such as apache and mysql can be reused on Windows, and the ports of RDP, IIS, etc. can not be reused temporarily.

The reused port can still provide its original service normally.

The first port reuse method

# Apache under windows environment: 
# Reuse apache 80 port, does not affect apache to provide normal http service
# The value of -h is the local ip, and can't be Otherwise, port reuse cannot be performed.
./agent.exe -lhost -reuse-port 80
./admin_macos_x64 -rhost -rport 80

The second port reuse method

# Apache under linux environment:
# Requires root privileges
sudo ./agent_linux_x64 -lport 8080 -reuse-port 80

This method will add the iptables rules, iptables forwards the traffic of the reuse-port to the lport, and then distribute the traffic by the agent.

One thing to note is that if the sigterm or sigint ends the agent (kill or ctrl-c), the agent will automatically clean up the iptables rules. If the agent is killed by kill -9, the iptables rule cannot be automatically cleaned up and needs to be cleaned manually because the agent program cannot deal with the sigkill signal.

In order to prevent the iptables rules from being automatically cleaned up and the penetration tester cannot access the 80-port service, the second port reuse method uses iptables -m recent to control whether the iptables forwarding rules are enabled through special tcp packets.

# Start the iptables port reuse rules set by the agent on the linux host
# If rhost is on the intranet, you can use the socks5 to proxy traffic. See the following for the use of the socks5 proxy.
python scripts/port_reuse.py --start --rhost --rport 80

# Connect to the agent
./admin_macos_x64 -rhost -rport 80

# If you want to turn off iptables port reuse rules
python scripts/port_reuse.py --stop --rhost --rport 80

2. admin node built-in commands

  • help (Print help information)
(admin node) >>> help

  help                                     Help information.
  exit                                     Exit.
  show                                     Display network topology.
  getdes                                   View description of the target node.
  setdes     [info]                        Add a description to the target node.
  goto       [id]                          Select id as the target node.
  listen     [lport]                       Listen on a port on the target node.
  connect    [rhost] [rport]               Connect to a new node through the target node.
  sshconnect [[email protected]:port] [dport]        Connect to a new node through ssh tunnel.
  shell                                    Start an interactive shell on the target node.
  upload     [local_file]  [remote_file]   Upload files to the target node.
  download   [remote_file]  [local_file]   Download files from the target node.
  socks      [lport]                       Start a socks5 server.
  lforward   [lhost] [sport] [dport]       Forward a local sport to a remote dport.
  rforward   [rhost] [sport] [dport]       Forward a remote sport to a local dport.
  • show (Display network topology)
The letter 'A' represents the admin node, and the number represents the agent node.

The following topology diagram shows that node1 connects to the admin node, node2 and node4 connect to 1 node, and node3 connects to node2.

(node 1) >>> show
+ -- 1
     + -- 2
          + -- 3
     + -- 4

Note that to operate on a newly joined node, first run the show command on the admin node to synchronize the network topology and node number.

  • goto (You want to operate a node)

(admin node) >>> goto 1
(node 1) >>> 

After going to a node, you can use the commands that will be described below.

  • getdes/setdes (Get/set node information description)

(node 1) >>> setdes linux x64 blahblahblah
(node 1) >>> getdes
linux x64 blahblahblah

  • connect/listen/sshconnect (Connect to another node/Accept connections from other nodes)
Node1 connects to port 9999 of

(node 1) >>> connect 9999
connect to 9999
successfully connect to the remote port!
(node 1) >>> show
+ -- 1
     + -- 2

Listening to port 9997 on the node1. Then run ./agent_linux_x64 -rhost -rport 9997 on another machine to connect to node1.

(node 1) >>> listen 9997
listen 9997
the port 9997 is successfully listening on the remote node!
(node 1) >>> show
+ -- 1
     + -- 2
     + -- 3

Execute ./agent_linux_x64 -lport 9999 on, then node3 connects to port 9998 of through the ssh tunnel using sshconnect command. You can use ssh or private key for ssh authentication.

(node 1) >>> goto 3
(node 3) >>> sshconnect [email protected]:22 9999
use password (1) / ssh key (2)? 2
file path of ssh key: /Users/dlive/.ssh/id_rsa

connect to target host's 9999 through ssh tunnel ([email protected]:22).
ssh successfully connects to the remote node!
(node 3) >>> show
+ -- 1
     + -- 2
     + -- 3
          + -- 4

  • shell (Get an interactive shell of the target node)
(node 1) >>> shell
You can execute commands in this shell :D, 'exit' to exit.
bash: no job control in this shell
bash-3.2$ whoami
bash-3.2$ exit
  • upload/download (Upload/download files from the target node)
Upload local /tmp/test.pdf to node1's /tmp/test2.pdf

(node 1) >>> upload /tmp/test.pdf /tmp/test2.pdf
upload /tmp/test.pdf to /tmp/test2.pdf
this file is too large(>100M), do you still want to upload it? (y/n)y
 154.23 MiB / 154.23 MiB [========================================] 100.00% 1s
upload file successfully!

Download node1's file /tmp/test2.pdf to your local /tmp/test3.pdf

(node 1) >>> download /tmp/test2.pdf /tmp/test3.pdf
download /tmp/test2.pdf from /tmp/test3.pdf
this file is too large(>100M), do you still want to download it? (y/n)y
 154.23 MiB / 154.23 MiB [========================================] 100.00% 1s
download file successfully!

  • socks (Establish a socks5 proxy on the target node)
(node 1) >>> socks 7777
a socks5 proxy of the target node has started up on local port 7777

After executing the socks command, a port will be opened locally on the admin node, such as 7777 above, using 7777 to perform the socks5 proxy.

  • lforward/rforward (Forward local port to remote / forward remote port to local)
Lforward forwards the local 8888 port of the admin node to the 8888 port of node1.

(node 1) >>> lforward 8888 8888
forward local network port 8888 to remote port 8888

Rforward forwards the port 8889 of the node1 network to the local 8889 port of the admin node.

(node 1) >>> rforward 8889 8889
forward remote network port 8889 to local port 8889

3. attention

  • Only one admin node is supported at this stage to manage the network.
  • To operate on a newly joined node, first run the show command on the admin node to synchronize the network topology and node number.
  • When using the second port reuse method (based on iptables), you need to use script/port_reuse.py to enable the port reuse rules set by the agent on the target host.


  • combined with regeorg
  • multiple administrator nodes
  • network traffic encryption
  • support socks5 udp
  • RESTful API
  • combined with meterpreter (to be discussed)


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