This action can be used to help you add some additional checks to help you secure your Docker Images in your CI. This would help you attain some confidence in your docker image before pushing them to your container registry or a deployment.
It internally uses Trivy
and Dockle
for running certain kinds of scans on these images.
Trivy
helps you find the common vulnerabilities within your docker images.Dockle
is a container linter, which helps you identify if you haven't followed- Certain best practices while building the image
- CIS Benchmarks to secure your docker image
Please checkout Trivy and Dockle licenses.
Action input | Description | Default Value |
---|---|---|
image-name |
(Required) The Docker image to be scanned | '' |
severity-threshold |
(Optional) Minimum severity threshold set to control flagging of the vulnerabilities found during the scan. The available levels are: (UNKNOWN, LOW, MEDIUM, HIGH, CRITICAL); if you set the severity-threshold to be `MEDIUM` every CVE found of a level higher than or equal to `MEDIUM` would be displayed | HIGH |
run-quality-checks |
(Optional) This is a boolean value. When set to `true` adds additional checks to ensure the image follows best practices and CIS standards. | true |
username |
(Optional) Username to authenticate to the Docker registry. This is only required when you're trying to pull an image from your private registry | '' |
password |
(Optional) Password to authenticate to the Docker registry. This is only required when you're trying to pull an image from your private registry | '' |
allowed-list |
(Optional) File path for the allowedlist | .github/containerscan/allowedlist.yaml |
The action generates an output file consisting of detailed description of all the detected vulnerabilities and best practice violations in JSON format. This file can be accessed by using the output variable scan-report-path
.
Here is a sample scan report:
{
"imageName": "myacr.azurecr.io/testapp:770aed6bd33d7240b4bdb55f16348ce37b86bb09",
"vulnerabilities": [
{
"vulnerabilityId": "CVE-2018-12886",
"packageName": "gcc-8-base",
"severity": "HIGH",
"description": "stack_protect_prologue in cfgexpand.c and stack_protect_epilogue in function.c in GNU Compiler Collection (GCC) 4.1 through 8 (under certain circumstances) generate instruction sequences when targeting ARM targets that spill the address of the stack protector guard, which allows an attacker to bypass the protection of -fstack-protector, -fstack-protector-all, -fstack-protector-strong, and -fstack-protector-explicit against stack overflow by controlling what the stack canary is compared against.",
"target": "myacr.azurecr.io/ascdemo:770aed6bd33d7240b4bdb55f16348ce37b86bb09 (debian 10.4)"
},
{
"vulnerabilityId": "CVE-2019-20367",
"packageName": "libbsd0",
"severity": "CRITICAL",
"description": "nlist.c in libbsd before 0.10.0 has an out-of-bounds read during a comparison for a symbol name from the string table (strtab).",
"target": "myacr.azurecr.io/ascdemo:770aed6bd33d7240b4bdb55f16348ce37b86bb09 (debian 10.4)"
},
{
"vulnerabilityId": "CVE-2020-1751",
"packageName": "libc-bin",
"severity": "HIGH",
"description": "An out-of-bounds write vulnerability was found in glibc before 2.31 when handling signal trampolines on PowerPC. Specifically, the backtrace function did not properly check the array bounds when storing the frame address, resulting in a denial of service or potential code execution. The highest threat from this vulnerability is to system availability.",
"target": "myacr.azurecr.io/ascdemo:770aed6bd33d7240b4bdb55f16348ce37b86bb09 (debian 10.4)"
}
],
"bestPracticeViolations": [
{
"code": "CIS-DI-0001",
"title": "Create a user for the container",
"level": "WARN",
"alerts": "Last user should not be root"
},
{
"code": "CIS-DI-0005",
"title": "Enable Content trust for Docker",
"level": "INFO",
"alerts": "export DOCKER_CONTENT_TRUST=1 before docker pull/build"
}
],
"vulnerabilityScanTimestamp": "2021-03-05T09:38:48.036Z"
}
In case you would like the action to ignore any vulnerabilities and best practice checks, create an allowedlist file (default .github/containerscan/allowedlist.yaml
) in your repo. Here's an example allowedlist.yaml file.
general:
vulnerabilities:
- CVE-2003-1307
- CVE-2007-0086
- CVE-2019-3462
- CVE-2011-3374
bestPracticeViolations:
- CIS-DI-0005
- DKL-LI-0003
- CIS-DI-0006
- DKL-DI-0006
Install Scanitizer (currently in Beta) on your repository for more convenient management of allowedlist file.
- uses: azure/container-scan@v0
with:
image-name: my-image:my-tag
- uses: azure/container-scan@v0
with:
image-name: loginServerUrl/my-image:${{ github.sha }} # loginServerlUrl/ would be empty if it's hosted on dockerhub; ${{ github.sha }} could also be replaced with any desired image tag
username: ${{ secrets.DOCKER_USERNAME }}
password: ${{ secrets.DOCKER_PASSWORD }}
Container scan of an image available locally, publically, or privately using workflow environment variables
- uses: azure/container-scan@v0
with:
image-name: ${{ env.loginServerUrl }}/my-image:${{ github.sha }} # ${{ env.loginServerUrl }}/ would be empty if it's hosted on dockerhub; ${{ github.sha }} could also be replaced with any desired image tag
username: ${{ secrets.DOCKER_USERNAME }}
password: ${{ secrets.DOCKER_PASSWORD }}
The following is an example of not just this action, but how this action could be used along with other actions to setup a CI.
Where your CI would:
- Build a docker image
- Scan the docker image for any security vulnerabilities
- Publish it to your private container registry.
on: [push]
jobs:
build-secure-and-push:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@master
- run: docker build . -t contoso.azurecr.io/k8sdemo:${{ github.sha }}
- uses: Azure/container-scan@v0
with:
image-name: contoso.azurecr.io/k8sdemo:${{ github.sha }}
- uses: Azure/docker-login@v1
with:
login-server: contoso.azurecr.io
username: ${{ secrets.REGISTRY_USERNAME }}
password: ${{ secrets.REGISTRY_PASSWORD }}
- run: docker push contoso.azurecr.io/k8sdemo:${{ github.sha }}
The following is an example of not just this action, but how this action could be used along with other actions to setup a CI.
Where your CI would:
- Build a docker image
- Scan the docker image for any security vulnerabilities
- Publish it to your preferred container registry.
This example assumes you have defined an evironment variable in your workflow for CONTAINER_REGISTRY
.
on: [push]
jobs:
build-secure-and-push:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@master
- run: docker build . -t ${{ env.CONTAINER_REGISTRY }}/k8sdemo:${{ github.sha }}
- uses: Azure/container-scan@v0
with:
image-name: ${{ env.CONTAINER_REGISTRY }}/k8sdemo:${{ github.sha }}
- uses: Azure/docker-login@v1
with:
login-server: ${{ env.CONTAINER_REGISTRY }}
username: ${{ secrets.REGISTRY_USERNAME }}
password: ${{ secrets.REGISTRY_PASSWORD }}
- run: docker push ${{ env.CONTAINER_REGISTRY }}/k8sdemo:${{ github.sha }}
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