alainlompo/splash

Splash Pseudo Lambda Shell

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  \__ \       / /_/ /     / /       / /| |       \__ \     / /_/ /      
 ___/ /      / ____/     / /___    / ___ |      ___/ /    / __  /      
/____/plash /_/seudo    /_____/   /_/  |_|mbda /____/    /_/ /_/ell  

A pseudo shell re-invoking the Lambda for each command.

For curious fellows who want to hack on AWS Lambda's infrastructure.

Features

• Supports CWD
• File transfers between the local machine and the Lambda
• Tracking Lambda writable file system (/tmp) resets
• Pretty colors

Why Not a Reverse Shell

Lambda is priced according to run time. A reverse shell running for a couple of minutes will be costly. Additionally, after some time the Lambda will timeout and the reverse shell connection will be closed.

Getting Started

Dependencies

Python3, requests.

$ sudo apt update && sudo apt install python3 python3-pip
$ pip3 install requests

Install and Setup

$ git clone https://github.com/twistlock/splash && cd splash

# Deploy ./deploy/aws/python3.7/lex.zip to an AWS Lambda through the aws CLI or the web UI.
# set Runtime:Python3.7, Handler:lex.handler, timeout:2min, and add an API Gateway trigger.

$ ./splash.py config addr <Lambda-addr>
$ ./splash.py  # run splash

Components

• splash.py - the shell.
• lex.py (Lambda Executor) - the Lambda function that executes splash's commands.
• deploy/aws/python3.7/lex.zip - a Lambda python package containing lex.

Other Platforms

1. Experimental support for Google Python3.7 Functions. To try, deploy deploy/gcp/python3.7/gcp_lex.zip to a function and set the function's handler to handler.

2. Experimental support for Azure Python3 Functions. To try, deploy the function app at deploy/azure/python3. This Function App contains one function, lex_func, which is the LEX agent. To deploy, you can use the Azure Portal UI to create an empty Linux Python Function App, and then deploy the LEX Function App through the Azure CLI by running: cd deploy/azure/python3; func azure functionapp publish <APP_NAME> --build remote.

Help

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  / ___/       / __ \      / /       /   |       / ___/     / / / /   
  \__ \       / /_/ /     / /       / /| |       \__ \     / /_/ /      
 ___/ /      / ____/     / /___    / ___ |      ___/ /    / __  /      
/____/plash /_/seudo    /_____/   /_/  |_|mbda /____/    /_/ /_/ell  

A pseudo shell re-invoking the Lambda for each command.
  -> SPLASH runs on your local machine.
  -> LEX (Lambda Executor) should run on your Lambda.

To support certain features splash will run simple commands on the Lambda behind the scenes
(e.g. 'whoami' to get the user name)

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# Configuration:
  -> splash config - get config
  -> splash config addr <lambda-addr>
  -> splash config trackfs <true/false> - track resets of the filesystem (the writable dir at '/tmp'), slows splash significantly.  
  -> splash config color <true/false> - enable/disable coloring

# Special Commands:
  -> Enter 'q' to exit. 
  -> Enter '!gt(b) <lambda-path> <local-path>' to get a file to your local machine, '--gtb' is for binary mode.
  -> Enter '!pt(b) <local-path> <lambda-path>' to put a file on the Lamda, '--ptb' is for binary mode.
  -> Enter '!help' to display this message while in a shell session

# Known Limitations:
  -> Currently only works with open API Gateway endpoints.
  -> Does not support enviroment variables.
  -> File transfers are limited to the Lambda's max request/response size (6MB). splash will try to tar larger files.
  If the file is still too large, consider running 'curl -F data=@path/to/lambda/file <your-server-address:port>' in splash.
  -> Limited support for CWD tracking. 
    * Supported by tracking 'cd' commands to identify the CWD, and then inserting "cd CWD; " to the start of shell commands.
    * Piping commands with 'cd' isn't supported (i.e. "cd /tmp ; echo A")
    * cd into an absolute path with '..' or '.' isn't supported (i.e. "cd /tmp/../tmp")
    * splash can get 'stuck' in a deleted directory, run 'cd' to reset CWD

TODO

• Add support for API Gateway authentication (API Key, IAM)