Security¶
Risks¶
CI/CD is the automation of most (if not all) process in your software lifecycle going from building to running the application in production. With so many things happening, attackers have a wide range of capabilities in case of a compromise:
- introduce dubious components (i.e. backdoor) in the application,
- leak (to the Internet) credentials granting access to internal services or infrastructures,
- access said services or infrastructures,
- impersonate an employee,
- leak intellectual property,
- ...
Every CI/CD job is executed inside a container image which contains various tools required by the job. When you are executing the job, you are trusting the people building the image and the tools.
In some cases, the image may have been corrupted by an attacker. This is what we call a supply chain attack. There are famous cases like the Codecov incident in which hackers managed to leak credentials from several services and cloud platforms.
Supply chain attacks can also occur when installing application dependencies in your CI/CD pipeline (Shai-Hulud).
Mitigations¶
Variables scoping¶
To prevent leakage, CI/CD variables has to be present only in jobs that need them. By example in the Maven template, only the mvn-sonar job actually needs the SONAR_TOKEN environment variable so others jobs (mvn-build, mvn-release...) should not access this secret.
You can find more info about how to protect your CI/CD variables in the official GitLab documentation.
Image selection¶
As much as we can, we try to select either official images (ex: Maven, Python), or at least images maintained by an active community. Each of those images can be freely overridden with the appropriate configuration variable to select fixed versions (more info here) or any alternative that would suit you more.
By default, to be continuous templates mostly use the latest tag from upstream images since it is a maintenance-less default that works for nearly everyone. However latest images are prone to supply chain attacks and are also likely to introduce breaking changes.
to be continuous is not responsible of any possible security issue from a default container image.
To mitigate the risks of using latest images, you should always use a fixed version tag (maven:3.9.1 instead of maven:latest) or build your own image.
Additional dependencies¶
However, the direct counterpart of using official images is that many default image do not ship all the required tools used by the template (think about git and curl utilities). For this reason, many templates check the presence of these additional dependencies and install them on the fly (see maybe_install_pkg function).
This is a good practice to avoid bloating the image with unnecessary tools, but it also means that you are trusting the upstream repositories of your distribution (i.e. Debian, Alpine, etc.) to not be compromised and requiring network access to download packages.
Every project is encouraged to maintain his own Docker image in order to fit to their needs, avoid extraneous downloading for additional dependencies and simplify the work of security team (it's easy to scan a Docker image). While doing so, we recommend to use a minimal distribution and root-less images to prevent some container escalation vulnerabilities against your runner provider.
Tip
Whenever building your own image or using an upstream image, you can use Renovate to watch updates for your tools, test the new version and integrate them seamlessly.
Application dependencies¶
Using lock files¶
We highly recommend using lock files (package-lock.json, yarn.lock, poetry.lock, etc.) to list all direct and transitive dependencies. These lock files should be commited to your git repositories. This ensures consistent installs between machines (including CI/CD pipelines).
When using lock files, the CI/CD pipelines based on to-be-continuous always use the dependencies versions listed in the lock file, they will never try to install newer versions of your dependencies (they use npm ci instead of npm install for example).
To add new dependencies, a developper needs to update the lock file directly on his development machine (the developper should run npm install or a similar command). Once done, this new lock file needs to be committed to the git repository.
To upgrade dependencies, we recommend using Renovate in a Gitlab CI pipeline. It will handle lock files for you.
Keep in mind that some templates might install dependencies not covered by project lock file.
Limit the risk of supply chain attack¶
When a dependency is compromised (Shai-Hulud for example), it is generally detected and removed from the repositories (NPM, PyPI, etc.) in the first hours/days after it has been published. A good practice is to configure your package managers (npm, yarn, poetry, etc.) on your development machines so that they do not download dependencies that have been published very recently. pnpm and yarn already support such settings.
Renovate also has a similar option when updating dependencies.
Vulnerability Reports (Trivy)¶
Important
When reviewing vulnerabilities from containers, you have to consider the following principes :
- containers are usually very short-lived in a CI/CD environment
- no direct user access is possible
- most job does not expose any exteral services (i.e. HTTP server) making attacks reliant on user interaction very hard if not impossible to exploit
In short, risks are often low in the CI/CD context but carefully reviewing vulnerabilities are an essential step to secure your pipeline.
Here are vulnerability reports for each default image used by to be continuous templates (generated every day):
| Template | Image Variable | Default Image | Vulnerabilities |
|---|---|---|---|
| Ansible | ANSIBLE_IMAGE | docker.io/cytopia/ansible:latest-tools |
5 High, 23 Medium, 1 Low |
| Ansible | ANSIBLE_LINT_IMAGE | docker.io/haxorof/ansible-lint:latest |
|
| Amazon Web Services | AWS_CLI_IMAGE | docker.io/amazon/aws-cli:latest |
|
| Azure | AZURE_CLI_IMAGE | mcr.microsoft.com/azure-cli:latest |
2 High, 2 Low |
| Bash | BASH_BATS_IMAGE | docker.io/bats/bats:latest |
3 Medium, 3 Low |
| Bash | BASH_SHELLCHECK_IMAGE | docker.io/koalaman/shellcheck-alpine:stable |
7 Medium, 5 Low |
| Bruno | BRU_IMAGE | docker.io/library/node:lts-alpine |
2 High, 1 Medium |
| GitLab Butler | BUTLER_IMAGE | registry.gitlab.com/to-be-continuous/tools/gitlab-butler:latest |
2 High, 4 Medium, 3 Low |
| Cloud Foundry | CF_CLI_IMAGE | docker.io/governmentpaas/cf-cli |
6 Critical, 35 High, 103 Medium, 3 Low |
| Cloud Native Buildpacks | CNB_BUILDER_IMAGE | docker.io/paketobuildpacks/builder-jammy-base:latest |
4 Critical, 111 High, 1937 Medium, 144 Low |
| Cloud Native Buildpacks | CNB_SKOPEO_IMAGE | quay.io/containers/skopeo:latest |
|
| Cloud Native Buildpacks | CNB_TRIVY_IMAGE | docker.io/aquasec/trivy:latest |
1 High |
| Cypress | CYPRESS_IMAGE | docker.io/cypress/included:13.13.3 |
30 Critical, 195 High, 386 Medium, 323 Low, 30 Unknown |
| dbt | DBT_IMAGE | ghcr.io/dbt-labs/dbt-core:latest |
4 Critical, 277 High, 1230 Medium, 669 Low, 6 Unknown |
| Docker Compose | DCMP_IMAGE | docker.io/library/docker:latest |
4 High, 9 Medium |
| Docker Compose | DCMP_KICS_IMAGE | docker.io/checkmarx/kics:latest |
|
| Debian | DEBIAN_BASE_IMAGE | docker.io/debian |
10 Medium, 50 Low |
| Debian | DEBIAN_BUILD_IMAGE | $DEBIAN_BASE_IMAGE |
not fetched |
| Debian | DEBIAN_LINT_IMAGE | $DEBIAN_BASE_IMAGE |
not fetched |
| DefectDojo | DEFECTDOJO_BASE_IMAGE | docker.io/library/node:alpine3.11 |
1 Critical, 25 High, 3 Medium, 2 Low |
| Dependency Track | DEPTRACK_SBOM_SCANNER_IMAGE | registry.gitlab.com/to-be-continuous/tools/dt-sbom-scanner:latest |
1 Medium |
| Docker | DOCKER_BUILDAH_IMAGE | quay.io/containers/buildah:latest |
|
| Docker | DOCKER_DIND_IMAGE | docker.io/library/docker:dind |
4 High, 9 Medium |
| Docker | DOCKER_HADOLINT_IMAGE | docker.io/hadolint/hadolint:latest-alpine |
7 Medium, 5 Low |
| Docker | DOCKER_IMAGE | docker.io/library/docker:latest |
4 High, 9 Medium |
| Docker | DOCKER_KANIKO_IMAGE | gcr.io/kaniko-project/executor:debug |
26 High, 75 Medium |
| Docker | DOCKER_SBOM_IMAGE | docker.io/anchore/syft:debug |
|
| Docker | DOCKER_SKOPEO_IMAGE | quay.io/containers/skopeo:latest |
|
| Docker | DOCKER_TRIVY_IMAGE | docker.io/aquasec/trivy:latest |
1 High |
| .NET | DOTNET_IMAGE | mcr.microsoft.com/dotnet/sdk:10.0 |
9 Medium, 17 Low |
| .NET | DOTNET_INFERSHARP_IMAGE | mcr.microsoft.com/infersharp:latest |
10 Critical, 53 High, 107 Medium, 114 Low, 7 Unknown |
| .NET | DOTNET_SBOM_IMAGE | ghcr.io/cyclonedx/cdxgen:master |
31 High, 63 Medium |
| .NET | DOTNET_SEMGREP_IMAGE | docker.io/semgrep/semgrep:latest |
3 High, 3 Medium |
| Google Cloud | GCP_CLI_IMAGE | gcr.io/google.com/cloudsdktool/cloud-sdk:latest |
4 Critical, 203 High, 743 Medium, 625 Low, 12 Unknown |
| Gitleaks | GITLEAKS_IMAGE | docker.io/zricethezav/gitleaks:latest |
1 High, 15 Medium, 3 Low |
| GitOps | GITOPS_IMAGE | docker.io/alpine/git:latest |
|
| GitLab Package | GLPKG_IMAGE | docker.io/curlimages/curl:latest |
3 Medium, 3 Low |
| Go | GO_CI_LINT_IMAGE | docker.io/golangci/golangci-lint:latest-alpine |
1 High, 2 Medium |
| Go | GO_IMAGE | docker.io/library/golang:bookworm |
2 Critical, 190 High, 698 Medium, 498 Low, 9 Unknown |
| Go | GO_SBOM_IMAGE | $GO_IMAGE |
not fetched |
| Go | GO_SEMGREP_IMAGE | docker.io/semgrep/semgrep:latest |
3 High, 3 Medium |
| Gradle | GRADLE_IMAGE | docker.io/library/gradle:latest |
84 Medium, 32 Low |
| Helmfile | HELMFILE_CLI_IMAGE | ghcr.io/helmfile/helmfile:latest |
2 Critical, 26 High, 111 Medium, 4 Low |
| Helm | HELM_CLI_IMAGE | docker.io/alpine/helm:latest |
4 High, 9 Medium, 5 Low, 2 Unknown |
| Helm | HELM_KUBE_SCORE_IMAGE | docker.io/zegl/kube-score |
8 Critical, 64 High, 112 Medium, 3 Low |
| Helm | HELM_YAMLLINT_IMAGE | docker.io/cytopia/yamllint |
9 High, 13 Medium |
| Hurl | HURL_IMAGE | ghcr.io/orange-opensource/hurl:latest |
3 Medium, 3 Low |
| k6 | K6_IMAGE | docker.io/grafana/k6:latest |
1 High, 6 Medium, 3 Low |
| Kubernetes | K8S_KUBECTL_IMAGE | docker.io/alpine/k8s:MUST_SET_VERSION |
not fetched |
| Kubernetes | K8S_KUBE_SCORE_IMAGE | docker.io/zegl/kube-score:latest |
8 Critical, 64 High, 112 Medium, 3 Low |
| Lighthouse | LHCI_IMAGE | docker.io/cypress/browsers:latest |
6 High, 39 Medium, 197 Low, 6 Unknown |
| GNU Make | MAKE_IMAGE | docker.io/alpinelinux/build-base |
|
| Maven | MAVEN_IMAGE | docker.io/library/maven:latest |
68 Medium, 32 Low |
| MkDocs | MKD_IMAGE | docker.io/squidfunk/mkdocs-material:latest |
|
| MkDocs | MKD_LYCHEE_IMAGE | docker.io/lycheeverse/lychee:latest |
1 Critical, 4 High, 20 Medium, 60 Low, 1 Unknown |
| MobSF | MOBSF_CLIENT_IMAGE | docker.io/badouralix/curl-jq |
4 Medium, 3 Low |
| MobSF | MOBSF_CODE_IMAGE | docker.io/opensecurity/mobsfscan:latest |
6 Critical, 463 High, 1567 Medium, 495 Low, 10 Unknown |
| Angular | NG_CLI_IMAGE | docker.io/trion/ng-cli-karma:latest |
2 Critical, 202 High, 712 Medium, 614 Low, 12 Unknown |
| Node.js | NODE_IMAGE | docker.io/library/node:lts-alpine |
2 High, 1 Medium |
| Node.js | NODE_SEMGREP_IMAGE | docker.io/semgrep/semgrep:latest |
3 High, 3 Medium |
| OSS Review Toolkit (ORT) | ORT_SCANNER_IMAGE | ghcr.io/oss-review-toolkit/ort:latest |
13 Critical, 91 High, 1626 Medium, 167 Low |
| OpenShift | OS_CLI_IMAGE | quay.io/openshift/origin-cli:latest |
8 High, 76 Medium, 185 Low |
| PHP | PHP_IMAGE | docker.io/library/php:latest |
87 High, 265 Medium, 424 Low, 9 Unknown |
| Playwright | PLAYWRIGHT_IMAGE | mcr.microsoft.com/playwright:latest |
6 High, 754 Medium, 153 Low |
| Postman | POSTMAN_IMAGE | docker.io/postman/newman:latest |
10 High, 31 Medium, 8 Low |
| pre-commit | PRE_COMMIT_IMAGE | docker.io/library/python:3-alpine |
|
| Puppeteer | PUPPETEER_IMAGE | ghcr.io/puppeteer/puppeteer:latest |
7 Critical, 249 High, 785 Medium, 805 Low, 12 Unknown |
| Python | PYTHON_IMAGE | docker.io/library/python:3-slim |
10 Medium, 51 Low |
| Renovate | RENOVATE_IMAGE | docker.io/renovate/renovate:latest |
1 High, 979 Medium, 78 Low |
| Robot Framework | ROBOT_BASE_IMAGE | docker.io/ppodgorsek/robot-framework:latest |
3 High |
| RPM | RPM_BASE_IMAGE | docker.io/fedora |
|
| RPM | RPM_BUILD_IMAGE | $RPM_BASE_IMAGE |
not fetched |
| RPM | RPM_LINT_IMAGE | $RPM_BASE_IMAGE |
not fetched |
| Rust | RUST_IMAGE | docker.io/library/rust:latest |
131 High, 366 Medium, 697 Low, 12 Unknown |
| Source-to-Image | S2I_DIND_IMAGE | docker.io/library/docker:dind |
4 High, 9 Medium |
| Source-to-Image | S2I_SKOPEO_IMAGE | quay.io/containers/skopeo:latest |
|
| Source-to-Image | S2I_TRIVY_IMAGE | docker.io/aquasec/trivy:latest |
1 High |
| S3 (Simple Storage Service) | S3_CMD_IMAGE | docker.io/d3fk/s3cmd:latest |
|
| Scala/SBT | SBT_IMAGE | docker.io/sbtscala/scala-sbt:17.0.2_1.6.2_3.1.3 |
53 Critical, 240 High, 359 Medium, 692 Low, 11 Unknown |
| Scala/SBT | SBT_SBOM_IMAGE | docker.io/anchore/syft:debug |
|
| semantic-release | SEMREL_IMAGE | docker.io/library/node:lts-slim |
1 Critical, 6 High, 21 Medium, 58 Low, 1 Unknown |
| SonarQube | SONAR_SCANNER_IMAGE | docker.io/sonarsource/sonar-scanner-cli:latest |
5 High, 2 Medium, 2 Low |
| Spectral | SPECTRAL_IMAGE | docker.io/stoplight/spectral:latest |
8 High, 29 Medium, 8 Low |
| Sphinx | SPHINX_IMAGE | ghcr.io/sphinx-doc/sphinx:latest |
24 Critical, 67 High, 75 Medium, 182 Low, 2 Unknown |
| Sphinx | SPHINX_LYCHEE_IMAGE | docker.io/lycheeverse/lychee:latest |
1 Critical, 4 High, 20 Medium, 60 Low, 1 Unknown |
| SQLFluff lint | SQLFLUFF_IMAGE | docker.io/sqlfluff/sqlfluff:latest |
3 Critical, 9 High, 34 Medium, 86 Low, 2 Unknown |
| Test SSL | TESTSSL_IMAGE | docker.io/drwetter/testssl.sh:latest |
|
| Terraform | TF_CHECKOV_IMAGE | docker.io/bridgecrew/checkov |
7 High, 34 Medium, 86 Low, 1 Unknown |
| Terraform | TF_DOCS_IMAGE | quay.io/terraform-docs/terraform-docs:edge |
|
| Terraform | TF_IMAGE | docker.io/hashicorp/terraform:latest |
|
| Terraform | TF_INFRACOST_IMAGE | docker.io/infracost/infracost |
72 Critical, 787 High, 749 Medium, 20 Low |
| Terraform | TF_PUBLISH_IMAGE | docker.io/curlimages/curl:latest |
3 Medium, 3 Low |
| Terraform | TF_TFLINT_IMAGE | ghcr.io/terraform-linters/tflint-bundle:latest |
7 Critical, 52 High, 181 Medium, 5 Low |
| Terraform | TF_TFSEC_IMAGE | docker.io/aquasec/tfsec-ci |
13 High, 37 Medium, 8 Low |
| Terraform | TF_TRIVY_IMAGE | docker.io/aquasec/trivy |
1 High |
| Zola | ZOLA_IMAGE | docker.io/jauderho/zola:latest |
|
| Zola | ZOLA_LYCHEE_IMAGE | docker.io/lycheeverse/lychee:latest |
1 Critical, 4 High, 20 Medium, 60 Low, 1 Unknown |