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Gato (Github Attack TOolkit)

Gato, or GitHub Attack Toolkit, is an enumeration and attack tool that allows both blue teamers and offensive security practitioners to identify and exploit pipeline vulnerabilities within a GitHub organization's public and private repositories.

The tool has post-exploitation features to leverage a compromised personal access token in addition to enumeration features to identify poisoned pipeline execution vulnerabilities against public repositories that use self-hosted GitHub Actions runners.

GitHub recommends that self-hosted runners only be utilized for private repositories, however, there are thousands of organizations that utilize self-hosted runners. Default configurations are often vulnerable, and Gato uses a mix of workflow file analysis and run-log analysis to identify potentially vulnerable repositories at scale.

Version 1.6

Gato version 1.6 improves the public repository enumeration feature set.

Previously, Gato's code search functionality by default only looked for yaml files that explicitly had "self-hosted" in the name. Now, the code search functionality supports a SourceGraph query. This query has a lower false negative rate and is not limited by GitHub's code search limit.

For example, the following query will identify public repositories that use self-hosted runners:

gato search --sourcegraph --output-text public_repos.txt

This can be fed back into Gato's enumeration feature:

gato enumerate --repositories public_repos.txt --output-json enumeration_results.json

Additionally the release contains several improvements under the hood to speed up the enumeration process. This includes changes to limit redundant run-log downloads (which are the slowest part of Gato's enumeration process) and using the GraphQL API to download workflow files when enumerating an entire organization. Finally, Gato will use a heuristic to detect if an attached runner is non-ephemeral. Most poisoned pipeline execution attacks require a non-ephemeral runner in order to exploit.

New Features

SourceGraph Search Functionality
Improved Public Repository Enumeration Speed
Improved Workflow File Analysis
Non-ephemeral self-hosted runner detection

Who is it for?

Security engineers who want to understand the level of access a compromised classic PAT could provide an attacker
Blue teams that want to build detections for self-hosted runner attacks
Red Teamers
Bug bounty hunters who want to try and prove RCE on organizations that are utilizing self-hosted runners

Features

GitHub Classic PAT Privilege Enumeration
GitHub Code Search API-based enumeration
SourceGraph Search enumeration
GitHub Action Run Log Parsing to identify Self-Hosted Runners
Bulk Repo Sparse Clone Features
GitHub Action Workflow Parsing
Automated Command Execution Fork PR Creation
Automated Command Execution Workflow Creation
Automated workflow secrets exfiltration
SOCKS5 Proxy Support
HTTPS Proxy Support

Getting Started

Installation

Gato supports OS X and Linux with at least Python 3.7.

In order to install the tool, simply clone the repository and use pip install. We recommend performing this within a virtual environment.

git clone https://github.com/praetorian-inc/gato
cd gato
python3 -m venv venv
source venv/bin/activate
pip install .

Gato also requires that git version 2.27 or above is installed and on the system's PATH. In order to run the fork PR attack module, sed must also be installed and present on the system's path.

Dev Branch

We maintain a development branch that contains newer Gato features that are not yet added to main. There is an increased chance you will run into bugs; however, we still run our integration test suite on the dev branch, so there should not be any blatant bugs.

If you want to use the dev branch, just check it out prior to running pip install - that's it!

If you do run into any for your specific use case, by all means open an issue!

Usage

After installing the tool, it can be launched by running gato or praetorian-gato.

We recommend viewing the parameters for the base tool using gato -h, and the parameters for each of the tool's modules by running the following:

gato search -h
gato enum -h
gato attack -h

The tool requires a GitHub classic PAT in order to function. To create one, log in to GitHub and go to GitHub Developer Settings and select Generate New Token and then Generate new token (classic).

After creating this token set the GH_TOKEN environment variable within your shell by running export GH_TOKEN=<YOUR_CREATED_TOKEN>. Alternatively, store the token within a secure password manager and enter it when the application prompts you.

For troubleshooting and additional details, such as installing in developer mode or running unit tests, please see the wiki.

Documentation

Please see the wiki. for detailed documentation, as well as OpSec considerations for the tool's various modules!

Bugs

If you believe you have identified a bug within the software, please open an issue containing the tool's output, along with the actions you were trying to conduct.

If you are unsure if the behavior is a bug, use the discussions section instead!

Contributing

Contributions are welcome! Please review our design methodology and coding standards before working on a new feature!

Additionally, if you are proposing significant changes to the tool, please open an issue open an issue to start a conversation about the motivation for the changes.

License

Gato is licensed under the Apache License, Version 2.0.

Copyright 2023 Praetorian Security, Inc

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.