Update step-security/harden-runner action to v2.21.0

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
step-security/harden-runner	action	minor	v2.17.0 → v2.21.0

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Release Notes

step-security/harden-runner (step-security/harden-runner)

v2.21.0

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v2.20.1

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What's Changed

• AWS CodeBuild-hosted runner support
• Implicitly allow single-labeled (internal) domains in block-mode

Full Changelog: step-security/harden-runner@v2.20.0...v2.20.1

v2.20.0

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What's Changed

• Support for block policy for MacOS and Windows GitHub-hosted runners
• Support for Bitrise MacOS GitHub Actions runners
• HTTPS monitoring support for Bun for Linux runners (enterprise tier)

Full Changelog: step-security/harden-runner@v2.19.4...v2.20.0

v2.19.4

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What's Changed

• Improvements for HTTPS Monitoring for the Enterprise tier of Harden Runner

Full Changelog: step-security/harden-runner@v2.19.3...v2.19.4

v2.19.3

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What's Changed

• Default to audit mode when api-key missing with use-policy-store by @​varunsh-coder in #​665

Full Changelog: step-security/harden-runner@v2.19.2...v2.19.3

v2.19.2

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What's Changed

• Update the Harden Runner agent for enterprise tier to use go 1.26 and fix minor bugs.

Full Changelog: step-security/harden-runner@v2.19.1...v2.19.2

v2.19.1

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What's Changed

• fix: detect ubuntu-slim runners early and bail out by @​devantler in #​657

What the fix changes

• Harden-Runner will detect ubuntu-slim runners and exit cleanly with an informational log message, instead of post harden runner step failing on chown: invalid user: 'undefined'.

What the fix does not do

• Jobs running on ubuntu-slim will not be monitored by Harden-Runner. The agent relies on kernel-level features (that require elevated capabilities).
• Per GitHub's docs on single-CPU runners: "The container for ubuntu-slim runners runs in unprivileged mode. This means that some operations requiring elevated privileges such as mounting file systems, using Docker-in-Docker, or accessing low-level kernel features are not supported." Those low-level kernel features are what the agent needs, so monitoring inside the unprivileged container is not feasible today.

For StepSecurity enterprise customers
If your security posture requires that workflows are always monitored, you can block the use of ubuntu-slim via workflow run policies see the Runner Label Policy docs. This lets you enforce that jobs only run on monitored runner types.

New Contributors

• @​devantler made their first contribution in #​657

Full Changelog: step-security/harden-runner@v2.19.0...v2.19.1

v2.19.0

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What's Changed

New Runner Support

Harden-Runner now supports Depot, Blacksmith, Namespace, and WarpBuild runners with the same egress monitoring, runtime monitoring, and policy enforcement available on GitHub-hosted runners.

Automated Incident Response for Supply Chain Attacks

• Global block list: Outbound connections to known malicious domains and IPs are now blocked even in audit mode.
• System-defined detection rules: Harden-Runner will trigger lockdown mode when a high risk event is detected during an active supply chain attack (for example, a process reading the memory of the runner worker process, a common technique for stealing GitHub Actions secrets).

Bug Fixes

Windows and macOS: stability and reliability fixes

Full Changelog: step-security/harden-runner@v2.18.0...v2.19.0

v2.18.0

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What's Changed

Global Block List: During supply chain incidents like the recent axios and trivy compromises, StepSecurity will add known malicious domains and IP addresses (IOCs) to a global block list. These will be automatically blocked, even in audit mode, providing immediate protection without requiring any workflow changes.

Deploy on Self-Hosted VM: Added deploy-on-self-hosted-vm input that allows the Harden Runner agent to be installed directly on ephemeral self-hosted Linux runner VMs at workflow runtime. This is intended as an alternative when baking the agent into the VM image is not possible.

Full Changelog: step-security/harden-runner@v2.17.0...v2.18.0

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