BinProxy - BinProxy is a proxy for arbitrary TCP connections

Friday, October 28, 2016


BinProxy is a proxy for arbitrary TCP connections. You can define custom message formats using the BinData gem.

Installation

Prerequisites
  • Ruby 2.3 or later
  • A C compiler, Ruby headers, etc., are needed to compile several dependencies.
    • On Ubuntu, sudo apt install build-essential ruby-dev should do it.
    • If you've installed a custom Ruby (e.g. with RVM), you probably already have what you need.
  • openssl binary for --tls without an explicit cert/key.
  • To build the UI, node.js and npm. (Not needed at runtime)

From Rubygems
gem install binproxy
You may need to use sudo , depending on your Ruby installation.

From Source
git clone https://github.com/nccgroup/BinProxy.git binproxy
cd binproxy

# Install ruby dependencies.
# Depending on your setup, one or both of these may require sudo.
gem install bundler && bundle

# The UI is built with a webpack/babel toolchain:
(cd ui && npm install) \
  && rake build-ui

# Confirm that everything works
# run.sh sets up the environment and passes all args to binproxy
./run.sh --help
To build and install the gem package:
gem build binproxy.gemspec

# Again, you may need sudo here
gem install binproxy-1.0.0.gem
Bug reports on installation issues are welcome!

Usage

Basic Usage
  1. Run binproxy with no arguments.
  2. Browse to http://localhost:4567/
  3. Enter local and remote hostnames or IP addresses and ports, and click 'update'
  4. Point a client at the local service, and watch the packets flow.

Command Line Flags
See --help for the complete list, but in short:
binproxy -c <class> [<local-host>] <local-port> <remote-host> <remote-port>
If you leave out the -c argument, a simple hex dump is shown.
If you leave out the local host, binproxy assumes localhost.
With the --socks-proxy or --http-proxy options, the remote host and port are determined dynamically, and should not be specified.

Examples
# Proxy from localhost:9000 -> example.com:9000
binproxy localhost 9000 example.com 9000

# Act as a SOCKS proxy on localhost:1080
# MITM and unwrap TLS on the proxied traffic, using a self-signed cert and key
binproxy -S --tls 1080

# "Poor substitute for Burp" mode:
#
# HTTP proxy; MITM TLS w/ pre-generated cert; simple header parsing
# Note: this will only work on HTTPS traffic, not plain HTTP!
# If you're working with the source repo, you generate the certs with:
#   rake makecert[example.com]
# And then import certs/ca-cert.pem into your browser or OS's trust store.
binproxy -H --tls \
  --tls-cert certs/example.com-cert.pem \
  --tls-key certs/example.com-key.pem \
  --class-name DumbHttp::Message \
  localhost 8080

Customizing
By default, the proxy uses the built-in RawMessage class, which just gives you a hexdump of each message (assuming 1:1 between messages and TCP packets)
You can view parsed protocol information by specifying a BinData::Record subclass† with the --class command line argument.
You may also wish to define the following in your class:
def summary
  # return a single-line description of this record
end

# currently supported options are
#   - nil : use default display
#   - "anon" : for structs, show contents directly
#   - "hex" : for numbers, display as 0x1234ABCD
#   - "hexdump" : for strings, display like `hexdump -C`
default_parameter display_as: "..."

# TODO: document state stuff
def self.initial_state
end

def current_state
end

def update_state
end
† Technically, any subclass of BinData::Base will work.

Dynamic Proxying
By default, BinProxy relays all traffic to a static upstream host and port. It can also be configured to act as a SOCKS (v4 or v4a) or HTTP proxy with the --socks-proxy and --http-proxy flags, respectively.
Note: Currently, the HTTP proxy only supports connections tunneled with the HTTP CONNNECT verb; it cannot proxy raw HTTP GET , POST , etc., requests. In practice, this means that HTTPS traffic will work, but plain HTTP traffic will not unless the client supports a flag to force tunneling, like curl -p .

TLS / SSL
Use the --tls flag to unwrap TLS encryption before processing messages. By default, BinProxy will generate a self-signed certificate. You can sepecify PEM files containing a certificate and key with --tls-cert and --tls-key . (If you've cloned the source repo, use rake makecert[example.com] to generate a static CA and a certificate with the appropriate hostname.)




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