Chain305

Chainsaw, from Chain305, is an open-source install-path firewall designed to stop malicious and misleading software packages before they are downloaded. Its local guard runs as a shell hook on a developer’s machine, without a daemon or internet connection, and supports npm, pip, Cargo, RubyGems, and Go. The CLI includes malicious-package intelligence and typosquat detection, and explains why an installation was refused.

For organizations, Chainsaw applies a shared, signed Rego policy across pull requests, package installation, hosted repository publishing, Kubernetes admission, and developer laptops. Policies can address vulnerabilities, licenses, versions, provenance, and other software supply-chain signals. Teams can begin in monitor mode, review audit records, and manage scoped exceptions, including expiry and optional two-person approval.

Chainsaw offers a registry proxy that extends enforcement across additional ecosystems, as well as deployment options including managed SaaS, a customer’s cloud environment, and air-gapped installations. Its capabilities include package inventory, signed SBOMs, audit evidence, and Enterprise SIEM exports.