Linux Security

Fast TCP tunnel over HTTP: Chisel

Chisel is a fast TCP tunnel, transported over HTTP, secured via SSH. Single executable including both client and server. Written in Go (golang). Chisel is mainly useful for passing through firewalls, though it can also be used to provide a secure endpoint into your network. Chisel is very similar to crowbar though achieves much higher performance.

 

 

Features

 

  • Easy to use
  • Performant*
  • Encrypted connections using the SSH protocol (via crypto/ssh)
  • Authenticated connections; authenticated client connections with a users config file, authenticated server connections with fingerprint matching.
  • Client auto-reconnects with exponential backoff
  • Client can create multiple tunnel endpoints over one TCP connection
  • Client can optionally pass through HTTP CONNECT proxies
  • Server optionally doubles as a reverse proxy
  • Server optionally allows SOCKS5 connections (See guide below)
  • Reverse port forwarding

To Install Chisel

Binaries:

Check the latest release or download and install it now with

 

 

Docker

 

Source

 

Demo:
demo app on Heroku is running this chisel server:

 

Chisel Usage:

 

 

Security

Encryption is always enabled. When you start up a chisel server, it will generate an in-memory ECDSA public/private key pair. The public key fingerprint will be displayed as the server starts. Instead of generating a random key, the server may optionally specify a key seed, using the --key option, which will be used to seed the key generation. When clients connect, they will also display the server’s public key fingerprint. The client can force a particular fingerprint using the --fingerprint option. See the --help above for more information.

 

Authentication

Using the --authfile option, the server may optionally provide a user.json configuration file to create a list of accepted users. The client then authenticates using the --auth option. See users.json for an example authentication configuration file. See the --help above for more information.

Internally, this is done using the Password authentication method provided by SSH. Learn more about crypto/ssh here http://blog.gopheracademy.com/go-and-ssh/.

 

 

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