README
¶
Clair
Note: The master branch may be in an unstable or even broken state during development.
Please use releases instead of the master branch in order to get stable binaries.
Clair is an open source project for the static analysis of vulnerabilities in appc and docker containers.
Vulnerability data is continuously imported from a known set of sources and correlated with the indexed contents of container images in order to produce lists of vulnerabilities that threaten a container. When vulnerability data changes upstream, the previous state and new state of the vulnerability along with the images they affect can be sent via webhook to a configured endpoint. All major components can be customized programmatically at compile-time without forking the project.
Our goal is to enable a more transparent view of the security of container-based infrastructure.
Thus, the project was named Clair after the French term which translates to clear, bright, transparent.
Common Use Cases
Manual Auditing
You're building an application and want to depend on a third-party container image that you found by searching the internet.
To make sure that you do not knowingly introduce a new vulnerability into your production service, you decide to scan the container for vulnerabilities.
You docker pull the container to your development machine and start an instance of Clair.
Once it finishes updating, you use the local image analysis tool to analyze the container.
You realize this container is vulnerable to many critical CVEs, so you decide to use another one.
Container Registry Integration
Your company has a continuous-integration pipeline and you want to stop deployments if they introduce a dangerous vulnerability. A developer merges some code into the master branch of your codebase. The first step of your continuous-integration pipeline automates the testing and building of your container and pushes a new container to your container registry. Your container registry notifies Clair which causes the download and indexing of the images for the new container. Clair detects some vulnerabilities and sends a webhook to your continuous deployment tool to prevent this vulnerable build from seeing the light of day.
Hello Heartbleed
During the first run, Clair will bootstrap its database with vulnerability data from its data sources. It can take several minutes before the database has been fully populated.
NOTE: These setups are not meant for production workloads, but as a quick way to get started.
Kubernetes
An easy way to run Clair is with Kubernetes 1.2+. If you are using the CoreOS Kubernetes single-node instructions for Vagrant you will be able to access the Clair's API at http://172.17.4.99:30060/ after following these instructions.
git clone https://github.com/coreos/clair
cd clair/contrib/k8s
kubectl create secret generic clairsecret --from-file=./config.yaml
kubectl create -f clair-kubernetes.yaml
Docker Compose
Another easy way to get an instance of Clair running is to use Docker Compose to run everything locally. This runs a PostgreSQL database insecurely and locally in a container. This method should only be used for testing.
$ curl -L https://raw.githubusercontent.com/coreos/clair/v1.2.4/docker-compose.yml -o $HOME/docker-compose.yml
$ mkdir $HOME/clair_config
$ curl -L https://raw.githubusercontent.com/coreos/clair/v1.2.4/config.example.yaml -o $HOME/clair_config/config.yaml
$ $EDITOR $HOME/clair_config/config.yaml # Edit database source to be postgresql://postgres:password@postgres:5432?sslmode=disable
$ docker-compose -f $HOME/docker-compose.yml up -d
Docker Compose may start Clair before Postgres which will raise an error.
If this error is raised, manually execute docker start clair_clair.
Docker
This method assumes you already have a PostgreSQL 9.4+ database running. This is the recommended method for production deployments.
$ mkdir $HOME/clair_config
$ curl -L https://raw.githubusercontent.com/coreos/clair/v1.2.4/config.example.yaml -o $HOME/clair_config/config.yaml
$ $EDITOR $HOME/clair_config/config.yaml # Add the URI for your postgres database
$ docker run -d -p 6060-6061:6060-6061 -v $HOME/clair_config:/config quay.io/coreos/clair:v1.2. -config=/config/config.yaml
Source
To build Clair, you need to latest stable version of Go and a working Go environment. In addition, Clair requires that bzr, rpm, and xz be available on the system $PATH.
$ go get github.com/coreos/clair
$ go install github.com/coreos/clair/cmd/clair
$ $EDITOR config.yaml # Add the URI for your postgres database
$ ./$GOBIN/clair -config=config.yaml
Container images
While container images for every releases are available at quay.io/repository/coreos/clair, container images built on the latest available source code are available at quay.io/repository/coreos/clair-git.
Documentation
The latest stable documentation can be found on the CoreOS website. Documentation for the current branch can be found inside the Documentation directory at the root of the project's source code.
Architecture at a Glance
Terminology
- Image - a tarball of the contents of a container
- Layer - an appc or Docker image that may or maybe not be dependent on another image
- Detector - a Go package that identifies the content, namespaces and features from a layer
- Namespace - a context around features and vulnerabilities (e.g. an operating system)
- Feature - anything that when present could be an indication of a vulnerability (e.g. the presence of a file or an installed software package)
- Fetcher - a Go package that tracks an upstream vulnerability database and imports them into Clair
Vulnerability Analysis
There are two major ways to perform analysis of programs: Static Analysis and Dynamic Analysis. Clair has been designed to perform static analysis; containers never need to be executed. Rather, the filesystem of the container image is inspected and features are indexed into a database. By indexing the features of an image into the database, images only need to be rescanned when new detectors are added.
Default Data Sources
| Data Source | Data Collected | Format | License |
|---|---|---|---|
| Debian Security Bug Tracker | Debian 6, 7, 8, unstable namespaces | dpkg | Debian |
| Ubuntu CVE Tracker | Ubuntu 12.04, 12.10, 13.04, 14.04, 14.10, 15.04, 15.10, 16.04 namespaces | dpkg | GPLv2 |
| Red Hat Security Data | CentOS 5, 6, 7 namespaces | rpm | CVRF |
| NVD | Generic Vulnerability Metadata | N/A | Public Domain |
Customization
The major components of Clair are all programmatically extensible in the same way Go's standard database/sql package is extensible.
Custom behavior can be accomplished by creating a package that contains a type that implements an interface declared in Clair and registering that interface in init(). To expose the new behavior, unqualified imports to the package must be added in your main.go, which should then start Clair using Boot(*config.Config).
The following interfaces can have custom implementations registered via init() at compile time:
Datastore- the backing storageNotifier- the means by which endpoints are notified of vulnerability changesFetcher- the sources of vulnerability data that is automatically importedMetadataFetcher- the sources of vulnerability metadata that is automatically added to known vulnerabilitiesDataDetector- the means by which contents of an image are detectedFeatureDetector- the means by which features are identified from a layerNamespaceDetector- the means by which a namespace is identified from a layer
Related Links
Talks & Slides
- Clair: The Container Image Security Analyzer @ ContainerDays Boston 2016 - Event Video Slides
- Identifying Common Vulnerabilities and Exposures in Containers with Clair @ CoreOS Fest 2016 - Event Video Slides
- Clair: A Container Image Security Analyzer @ Microservices NYC - Event Video Slides
- Clair: A Container Image Security Analyzer @ Container Orchestration NYC - Event Video Slides
Projects Integrating with Clair
- Quay: the first container registry to integrate with Clair
- Dockyard: an open source container registry with Clair integration
- Hyperclair: a lightweight command-line tool for working locally with Clair
- Clair w/ SQS: a container containing Clair and additional processes that integrate Clair with Amazon SQS
- Klar: a simple command-line integration of Clair and Docker registry, designed to be used in scripts and CI
Documentation
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Source Files
Directories
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| Path | Synopsis |
|---|---|
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v1
Package v1 implements the first version of the Clair API.
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Package v1 implements the first version of the Clair API. |
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cmd
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contrib
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Package database defines the Clair's models and a common interface for database implementations.
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Package database defines the Clair's models and a common interface for database implementations. |
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pgsql
Package pgsql implements database.Datastore with PostgreSQL.
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Package pgsql implements database.Datastore with PostgreSQL. |
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pgsql/migrations
Package migrations regroups every migrations available to the pgsql database backend.
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Package migrations regroups every migrations available to the pgsql database backend. |
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Package notifier fetches notifications from the database and informs the specified remote handler about their existences, inviting the third party to actively query the API about it.
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Package notifier fetches notifications from the database and informs the specified remote handler about their existences, inviting the third party to actively query the API about it. |
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notifiers
Package notifiers implements several kinds of notifier.Notifier
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Package notifiers implements several kinds of notifier.Notifier |
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Package updater updates the vulnerability database periodically using the registered vulnerability fetchers.
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Package updater updates the vulnerability database periodically using the registered vulnerability fetchers. |
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Package utils simply defines utility functions and types.
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Package utils simply defines utility functions and types. |
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errors
Package errors defines error types that are used in several modules
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Package errors defines error types that are used in several modules |
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http
Package http provides utility functions for HTTP servers and clients.
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Package http provides utility functions for HTTP servers and clients. |
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oval
This package contains the OvalFetcher definition which is being used for fetching update information on OVAL format see: https://oval.mitre.org/about/faqs.html#a1 Example of an oval definition <oval_definitions xmlns=.....> <definitions> <definition> <metadata> <title>CVE-1111-11</title> <description>blablabla</description> <reference source="CVE" ref_id="CVE-1111-11" ref_url="http...."/> <reference source="RHSA" ref_id="RHSA-111:11" ref_url="http...."/> </metadata> <criteria operator="AND"> <criterion test_ref="123" comment="glibc is ...."> </criterion> <criterion test_ref="456" comment="....
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This package contains the OvalFetcher definition which is being used for fetching update information on OVAL format see: https://oval.mitre.org/about/faqs.html#a1 Example of an oval definition <oval_definitions xmlns=.....> <definitions> <definition> <metadata> <title>CVE-1111-11</title> <description>blablabla</description> <reference source="CVE" ref_id="CVE-1111-11" ref_url="http...."/> <reference source="RHSA" ref_id="RHSA-111:11" ref_url="http...."/> </metadata> <criteria operator="AND"> <criterion test_ref="123" comment="glibc is ...."> </criterion> <criterion test_ref="456" comment=".... |
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types
Package types defines useful types that are used in database models.
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Package types defines useful types that are used in database models. |
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Package worker implements the logic to extract useful informations from a container layer and store it in the database.
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Package worker implements the logic to extract useful informations from a container layer and store it in the database. |
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detectors
Package detectors exposes functions to register and use container information extractors.
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Package detectors exposes functions to register and use container information extractors. |