SBOM on

Find a Matching Chainguard Image Using the API

Tue, 26 May 2026 00:00:00 +0000

This guide walks through calling the Chainguard Image Matcher API to find the best Chainguard equivalent for an existing container image. It assumes you already have an SBOM for the image you want to migrate.

For background on how the matcher works and how it scores recommendations, see Image Matcher Overview.

Prerequisites

Before getting started, you will need:

What is an SBOM (software bill of materials)?

Thu, 04 Aug 2022 15:21:01 +0200

Modern software applications contain hundreds to thousands of open source and third-party components, creating significant security challenges that SBOMs help address - which is why Chainguard includes comprehensive SBOMs with every container image. Without structured visibility into these components, organizations struggle to identify and respond to vulnerabilities, even when patches are available. This lack of transparency leaves systems vulnerable to exploitation, making SBOMs essential for maintaining secure software supply chains.

How to Sign an SBOM with Cosign

Wed, 13 Jul 2022 15:22:20 +0100

An earlier version of this material was published in the Cosign chapter of the Linux Foundation Sigstore course.

Cosign, developed as part of the Sigstore project, is a command line utility for signing, verifying, storing, and retrieving software artifacts through interface with an OCI (Open Container Initiative) registry. Cosign can be used to sign attestations, or a verifiable assertion or statement about a software artifact.

What is an Attestation?

An attestation is a cryptographically verifiable statement about a software artifact. Attestations include a subject, a software artifact or artifacts to which the attestation applies, and a predicate, a claim or proposition about the subject. For example, an attestation might assert that a specific container image was built on a specific date using a specific configuration, and that assertion could be cryptographically verified as issuing from a specific organization or entity.

Image Matcher Overview

Tue, 26 May 2026 00:00:00 +0000

The Chainguard Image Matcher is an API-based tool that analyzes the software bill of materials (SBOM) of an existing container image and returns a ranked list of Chainguard images that most closely match it. It is designed to support migration workflows where you know what you are running today and want to find the best Chainguard equivalent.

How it works

You supply an SBOM for your current image, along with the source Linux distribution. The Image Matcher maps the packages in your SBOM to Chainguard APK packages, scores each candidate Chainguard image based on how well its contents cover your requirements, and returns a ranked list of recommendations with confidence scores.

Rego Policies

Thu, 12 Jan 2023 15:56:52 -0700

The Sigstore Policy Controller supports the Rego Policy Language, which is a declarative policy language that is used to evaluate structured input data such as Kubernetes manifests and JSON documents. This feature enables users to apply policies that can evaluate Kubernetes admission requests and object metadata to make comprehensive decisions about the workloads that are admitted to their clusters. Rego support also enables users to enhance existing cloud-native policies by adding additional software supply chain security checks.

Getting Started with OpenVEX and vexctl

Mon, 30 Jan 2023 15:21:01 +0200

The vexctl CLI is a tool to make VEX work. As part of the open source OpenVex project, vexctl enables you to create, apply, and attest VEX (Vulnerability Exploitability eXchange) data in order to filter out false positive security alerts.

The vexctl tool was built to help with the creation and management of VEX documents, communicate transparently to users as time progresses, and enable the “turning off” of security scanner alerts of vulnerabilities known not to affect a given product. Using VEX, software authors can communicate to their users that an otherwise vulnerable component has no security implications for their product.

What Makes a Good SBOM?

Thu, 04 Aug 2022 15:21:01 +0200

A software bill of materials, or an SBOM (pronounced s-bomb), is a formal record of the components contained in a piece of software. It is analogous to an ingredients list for a recipe. And it has become recognized as one of the key building blocks of software supply chain security. Proponents rightfully point out that organizations can’t secure their software if they don’t know what’s inside their software.

As awareness and adoption of SBOM has grown, there has been a gradual acknowledgement that not all SBOMs are created equal, some are more or less useful, depending on the goals of the SBOM user and the contents of the SBOM. This guide exists to provide some guidance on evaluating the quality of an SBOM, suggesting common use cases and the data fields that support these use cases and open source SBOM quality tools.

What is OpenVex?

Tue, 31 Jan 2023 15:21:01 +0200

OpenVEX is an open source specification, library, and suite of tools designed to enable software users to eliminate vulnerability noise and focus their security efforts on vulnerabilities that pose an immediate risk. Released by Chainguard in January 2023, it’s the first set of open source tools to support the VEX specification championed by the United States National Telecommunications and Information Administration (NTIA) and the Cybersecurity and Infrastructure Security Agency (CISA).

With OpenVEX, stakeholders from across the software supply chain can collaborate on identifying and remediating exploitable vulnerabilities and use automation to enable more precise and efficient methods of security management. In this guide, you will learn more about the emerging supply chain security standards that OpenVEX supports, as well as how OpenVEX tooling can help you leverage them in your security management processes.

The Differences between SBOMs and Attestations

Sun, 19 Mar 2023 15:56:52 -0700

One of the first steps to improving your software supply chain security is to establish a process for creating quality Software Bills of Materials (SBOMs). An SBOM is a formal record that contains the details and supply chain relationships (such as dependencies) of the components used in building software.

Cosign — a part of the Sigstore project — supports software artifact signing, verification, and storage in an OCI (Open Container Initiative) registry. The cosign command line tool offers two subcommands that you can use to associate an SBOM with a container image and then upload them to a registry: cosign attach and cosign attest.

Example Policies

Fri, 15 Jul 2022 15:22:20 +0100

The Sigstore Policy Controller allows users to create their own security policies that they can be enforced on Kubernetes clusters. Here are a few example policies to help you get started.

You may also review the Sigstore Policy Controller documentation. In particular, we encourage you to review the Policy Controller documentation relating to the Admission of images to learn how to admit images through the cluster image policy.

Policy enforcing signed containers

apiVersion: policy.sigstore.dev/v1beta1
kind: ClusterImagePolicy
metadata:
name: signed-keyless
spec:
images:
# All images
- glob: "**"
authorities:
- keyless:
url: https://fulcio.sigstore.dev
ctlog:
url: https://rekor.sigstore.dev

Example using Chainguard Containers from Chainguard’s registry:

How to Retrieve SBOMs and attestations for Chainguard Containers

Fri, 17 Nov 2023 11:07:52 +0200

Chainguard provides a Software Bill of Materials (SBOM) with every container image, enabling complete transparency about package contents and dependencies for security and compliance requirements. These SBOMs are cryptographically signed and attached as attestations, making them retrievable and verifiable. By including only the minimum packages needed, Chainguard Containers reduce attack surface while the SBOM ensures you can verify exactly what’s in each image.

Even though they contain the minimum number of packages, there may come a time when you want to know exactly what’s running inside of a certain Chainguard Container. For this reason, Chainguard includes a signed SBOM with each image in the form of a software attestation, allowing you to verify the contents and meet compliance requirements. Chainguard publishes several different types of attestations; see the options under the Available attestation types section on this page.

SBOMs

Thu, 26 Jan 2023 08:49:15 +0000

A software bill of materials, or an SBOM (pronounced s-bomb), is a key resource for enabling visibility into the different software components of a codebase.