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Automated security decision-making under uncertainty.

🏰 What is Bulwark?

Bulwark is a fast, modern, open-source web application firewall (WAF) and API security gateway. It simplifies the implementation of detective security controls while offering comprehensive visibility into your web services. Bulwark's detection-as-code approach to rule definition offers security teams higher confidence in their response to persistent and adaptive threats. Bulwark plugins offer a wide range of capabilities, enabling security teams to define and evolve detections rapidly, without making changes to the underlying application.

• Open Source. Freely available under a permissive Apache 2.0 license. We're committed to keeping it that way.
• Extensible. Define custom detection logic using the SDK, or customize reusable parameterized detections to your needs, without writing code.
• Observable. Gain comprehensive visibility into both your traffic and the operation of your detections with built-in observability features. Enrich your traffic data for improved context.
• Flexible. Bulwark's plugin API enables detections to interact with Redis state and other services, including machine learning models. Plugins can perform their detections collaboratively using Bulwark's ensemble decisions. Securely decrypt session cookies to operate on application-level information.
• Testable. Detections can have automated tests. Prevent misclassifications from making it to production.
• Accurate. Bulwark has built-in mechanisms to help tune detections for high accuracy, minimize false positives, and quickly remediate accuracy issues if they occur. Meet compliance requirements for detective controls while avoiding false positives that would disrupt operations.
• Sandboxed. Every detection runs inside a secure WebAssembly sandbox, isolating detection logic, and ensuring that access never exceeds its permissions grants.
• Safe. Deploy in observe-only mode and build confidence in the system before enabling request blocking.
• Commercially Supported. Bulwark is actively developed and supported by Bulwark Security PBC. We intend to offer a freely available community ruleset, an advanced commercial ruleset, paid support, and professional services, in addition to a Bulwark cloud admin application. Contact us (hello@bulwark.security) if you are interested in discounted early access on a design partner basis for any of these commercial offerings.

🕵️ Use Cases

• Account Takeover: Detect patterns of abuse like credential stuffing, password spraying, session hijacking, and phishing that target account login pages, authentication APIs, or make use of stolen cookies. Reduce time spent responding to these threats.
• Site Scraping: Identify and block bots that are ignoring robots.txt or scraping site data at abnormal frequencies, without negatively affecting well-behaved bots and crawlers. This is especially relevant for users that may be concerned about their sites being incorporated into training data without authorization.
• Free-Tier Abuse: Prevent abusive free-tier usage from making such offerings unsustainable. Send the results of runtime detective controls to a Bulwark plugin, where it can be combined with CAPTCHAs and other signals to help identify these behaviors earlier, before they consume limited resources.
• Combine Fraud Signals: Take advantage of Bulwark's ability to access external services to seamlessly combine fraud scoring from independent vendors. Protect interior services from high-volume automated fraud like card testing that may otherwise affect availability.
• Block Exploits: Bulwark can be used as a WAF to detect and block exploits targeting XSS, SQL injection, and other common vulnerabilities.

💻 Installation

1. Install the Rust toolchain via rustup.
2. Install the wasm32-wasi target needed to build plugins: rustup target add wasm32-wasi
3. Install Bulwark: cargo install bulwark-cli

🚀 Quickstart

In a Bulwark deployment, there are several pieces working together. In the current version of Bulwark, Envoy handles the initial HTTP request processing. Bulwark uses Envoy's external processing API to hook that processing and perform security decision-making on the traffic. In most configurations, there will be an interior service that handles the actual business logic of the web application and Envoy will be configured to send the traffic onwards once Bulwark has made its decision. It's recommended to use Bulwark alongside a Redis server to maintain state across multiple Bulwark instances, although this is not strictly necessary if Bulwark is only used with stateless detection plugins.

An example Envoy configuration file is provided as a starting point for the typical deployment setup just described. The Envoy server would be launched with the following command:

envoy -c envoy.yaml

Bulwark's own configuration file is a TOML file that defines which detection plugins should be used to process a request, as well as details like the listening port and the address for the Redis server. The listening port in Bulwark's configuration must match the port number given for the corresponding external processing filter section in Envoy's configuration. Bulwark is launched with the following command:

bulwark-cli ext-processor -c bulwark.toml

Bulwark plugins are compiled to WebAssembly before use. While it's recommended to do this using a workflow like GitHub Actions, you can also do this manually, particularly for development. To compile a Bulwark plugin:

bulwark-cli build -p rules/example-plugin -o dist/plugins/

💪 Contributing

Check out the list of open issues. We actively maintain a list of issues suitable for new contributors to the project. Alternatively, detection plugins may be contributed to the community ruleset.

We do not require contributors to sign a license agreement (CLA) because we want users of Bulwark to be confident that the software will remain available under its current license.

🤝 License

This project is licensed under the Apache 2.0 license with the LLVM exception. See LICENSE for more details.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this project by you, as defined in the Apache 2.0 license, shall be licensed as above, without any additional terms or conditions.

🛟 Getting Help

To start, check if the answer to your question can be found in any of the guides or API documentation. If you aren't able to find an answer there, check the Bulwark project's discussion forum. We are happy to help answer your questions and provide guidance through our community forum.