clairproject.org

What It Is

Clair is a free, open-source static vulnerability scanner for container images. It follows the “do one thing and do it well” design philosophy, focusing on in-depth analysis of container image contents to detect known vulnerabilities at both the operating system and programming language levels. It helps provide software supply chain transparency and a security baseline for cloud-native applications.

Key Features

• Protection type: Clair focuses on continuous static analysis (CSA) of container images. It can identify vulnerabilities in base operating systems such as RHEL, Alpine, and Ubuntu, installed packages, and multiple programming language ecosystems including Python, Java, Golang, and JS. It does not provide runtime protection.
• Deployment options: Its architecture is highly flexible, supporting deployment as microservices, a monolith, within CI pipelines, and in disconnected/offline environments. Its core runtime is packaged as the ClairCore Go module, making it easy for developers to embed directly into their own applications.
• Integration capabilities: Clair is compatible with the OCI Distribution and Docker v2 specifications, and can work with major container registries such as quay.io and ECR. It provides a RESTful API for integration into most runtime architectures.
• Scale and use cases: It is highly scalable, capable of serving some of the largest container image registries on the internet while also being suitable for smaller environments such as personal laptops or CI pipelines.
• Management and alerting: Clair continuously monitors newly published vulnerabilities in the background and updates its database, enabling fast re-analysis without re-reading the entire image. However, the source text does not explicitly mention a native alert push mechanism, so alerting would need to be integrated via the API.
• Compliance certifications: The source text does not mention any relevant compliance certifications.

Pricing

Clair is licensed under the Apache 2.0 open-source license and is completely free. This allows the community to contribute freely and also permits free use across a wide range of commercial and personal scenarios.

Pros and Cons

Pros: 100% open source and free; purpose-built for containers with accurate scanning; efficient incremental analysis that avoids repeatedly reading images; highly extensible modular architecture with separate Indexer and Matcher components.
Cons: Limited to static analysis and cannot cover runtime threats; due to differences in vulnerability data sources and matching mechanisms, scan results may differ from those of commercial tools; Ruby language support is still under development; lacks an out-of-the-box alert notification system.

Who It’s For

Clair is suitable for containerized development and operations teams that need to build a secure software supply chain, especially teams looking to integrate automated vulnerability scanning into CI/CD pipelines or enterprises operating private or public container image registries.

Access from China

The source text does not clearly state any network access restrictions. As an open-source project, the code is typically hosted on platforms such as GitHub, where access from mainland China may be unstable or require a proxy; the exact status is unknown. There is no relevant commercial payment process involved. Comparable alternatives include Trivy and Anchore.