Baish (Bash AI Shield)

curl thisisapotentiallyunsafescript.com/script.sh | baish -s | bash

Baish is a security-focused tool that uses Large Language Models (LLMs) and other heuristics to analyse shell scripts before they are executed. It's designed to be used as a more secure alternative to the common curl | bash pattern.

Importantly, Baish is a cybersecurity learning project, where the developers have a relatively narrow solution to implement, but still learn a lot about the problem space. For example, how to use LLMs, how to secure them, and how to take and understand untrusted input.

About TAICO

The Toronto Artificial Intelligence and Cybersecurity Organization (TAICO) is a group of AI and cybersecurity experts who meet monthly to discuss the latest trends and technologies in the field. Baish is a project of TAICO.

Installation

Prerequisites

• An API key from a supported LLM provider, e.g. Cohere,OpenAI, Anthropic, Groq, etc. or a local LLM.
• Knowing which model from the provider you are going to use.
• Python 3.10 or later
• pip or pip3 installed
• libmagic (for file type detection)
  • Ubuntu/Debian: apt install libmagic1
  • RHEL/CentOS: dnf install file-libs
  • macOS: brew install libmagic

Install

• Ensure to have the prerequisites installed
• Install with pipx is recommended
• Install with pip is also supported

Prerequisites

Ensure you have prerequisites installed. Currently the install script won't install the prerequisites for you.

On Linux:

sudo apt install libmagic1 -y

On macOS:

brew install libmagic

Install with pipx

First, install pipx. There are instructions for Mac, Linux, and Windows on the pipx website.

Then, install baish with pipx:

pipx install baish

Follow the pipx instructions to setup the alias in your shell, and at that point you can run baish as normal.

Install with pip

NOTE: It's recommended to use pipx to install baish, as it creates a virtual environment to install the dependencies in.

pip install baish

Configure

Create the ~/.baish directory:

mkdir ~/.baish

Ensure to set your API key in your environment variables, e.g. export OPENAI_API_KEY=... or export ANTHROPIC_API_KEY=...

Edit the ~/.baish/config.yaml file to your liking.

e.g. use the haiku model from Anthropic:

default_llm: haiku # default model to use
llms:
  haiku: # memorable name
    provider: anthropic # provider name
    model: claude-3-5-haiku-latest # model name
    temperature: 0.1 # temperature

Now you can run baish!

Usage

• Technically, you can pipe any file to baish, but it's really meant to be used with shell scripts, especially via the curl evil.com/evil.sh | baish pattern.

curl -sSL https://thisisapotentiallyunsafescript.com/script.sh | baish

Baish will output the harm score, complexity score, and an explanation for why the script is either safe or not.

You can also run using the --input flag, which will read from a file instead of stdin.

baish --input some-script.sh

Setting Provider and Model

You can set the provider and model in the config.yaml file.

E.g. config.yaml:

default_llm: haiku # default model to use
llms:
  haiku: # memorable name
    provider: anthropic # provider name
    model: claude-3-5-haiku-latest # model name
    temperature: 0.1 # temperature

  other_model:
    provider: groq
    model: llama3-70b-8192
    temperature: 0.1

Example Output

Here's an example of the output of a real world script that Baish analyzed. In fact, it's the install script for Baish itself!

$ curl -sSL https://raw.githubusercontent.com/taicodotca/baish/main/install.sh | baish 
⠋ Analyzing file...
╭──────────────────────────────── Baish - Bash AI Shield ────────────────────────────────╮
│ Analysis Results - 2024-12-21_06-55-35_e9fa19e5_script.sh                              │
│                                                                                        │
│ Harm Score:       2/10 ████────────────────                                            │
│ Complexity Score: 8/10 ████████████████────                                            │
│ Uses Root:    False                                                                    │
│                                                                                        │
│ File type: text/x-shellscript                                                          │
│                                                                                        │
│ Explanation:                                                                           │
│ The script is a bash installer for baish, a tool that sets up a Python virtual         │
│ environment and installs baish. It checks for system dependencies, Python              │
│ requirements, and installs baish using pip. It also sets up an alias for baish in the  │
│ user's shell configuration file.                                                       │
│                                                                                        │
│ Script saved to: /home/curtis/.baish/scripts/2024-12-21_06-55-35_e9fa19e5_script.sh    │
│ To execute, run: bash                                                                  │
│ /home/curtis/.baish/scripts/2024-12-21_06-55-35_e9fa19e5_script.sh                     │
│                                                                                        │
│ ⚠️  AI-based analysis is not perfect and should not be considered a complete security   │
│ audit. For complete trust in a script, you should analyze it in detail yourself. Baish │
│ has downloaded the script so you can review and execute it in your own environment.    │
╰────────────────────────────────────────────────────────────────────────────────────────╯

Caveats and Disclaimers

⚠️ Baish's analysis is not foolproof! This is a proof of concept! To be completely sure that a script is safe, you would have to review and analyze it yourself.

⚠️ Different LLM providers will give different results. One provider and one model may give a script a low risk score, while another model or provider gives a high risk score. You would have to experiment with different providers and models to see which one you trust the most.

⚠️ Baish is in heavy development. Expect breaking changes.

⚠️ Using local Ollama for local LLMs is still experimental and may not work as expected, mostly due to small context windows.

Documentation

See the docs for more information.