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.
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.
- SourceGraph Search Functionality
- Improved Public Repository Enumeration Speed
- Improved Workflow File Analysis
- Non-ephemeral self-hosted runner detection
- 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
- 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
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.
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!
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 -hgato enum -hgato 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.
Please see the wiki. for detailed documentation, as well as OpSec considerations for the tool's various modules!
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!
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.
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.