These incidents made it clear that a purpose-built security agent was needed for CI/ CD. While there are numerous agents available for desktops and servers, such as from CrowdStrike and Lacework, none have been tailored specifically to address the unique risks present in CI/CD pipelines.

With the understanding that a specialized solution was needed to secure CI/CD environments, we developed Harden-Runner, an open-source solution tailored specifically for GitHub Actions hosted runners. It can be seamlessly integrated into your workflow by simply adding a step. The agent installation process is also lightning-fast, taking no more than 5 seconds to complete.

Harden-Runner's security agent is designed to closely monitor all aspects of the workflow run, including DNS, network, file, and process events. This allows for real-time identification of any potential security breaches. To prevent incidents like the Codecov breach, where exfiltration of credentials occurred, Harden-Runner allows you to set policies that restrict outbound traffic at both the DNS and network layers. Additionally, we are actively working on implementing further restrictions at the application layer, such as using HTTP verbs and paths, to provide an even more comprehensive security solution.

An excellent example of how Harden-Runner effectively blocks outbound traffic can be found in the following link: https://app.stepsecurity.io/github/microsoft/msquic/actions/.... As you can see, all traffic to unauthorized endpoints is highlighted in red, indicating that it has been blocked; this is because these endpoints are not included in the allowed list defined in the GitHub Actions workflow file, which can be viewed here: https://github.com/microsoft/msquic/blob/aaecb0fac5a3902dd24....

One of the key features of Harden-Runner's monitoring capabilities is its ability to detect any tampering or alteration of files during the build process, similar to the SolarWinds incident. To further enhance security and protect against potential malicious tools or attempts to disable the agent, Harden-Runner includes a disable-sudo mode. This mode effectively disables the use of 'sudo' on the hosted runner, providing an additional layer of protection

Harden-Runner has already been adopted by over 600 open-source repositories: https://github.com/step-security/harden-runner/network/depen.... To fully understand the capabilities of Harden-Runner and how it can protect against past supply chain attacks, please try out our attack simulator GitHub repository at https://github.com/step-security/attack-simulator. I would love to hear your feedback.