AWS - Codebuild Enum

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CodeBuild

AWS CodeBuild is recognized as a fully managed continuous integration service. The primary purpose of this service is to automate the sequence of compiling source code, executing tests, and packaging the software for deployment purposes. The predominant benefit offered by CodeBuild lies in its ability to alleviate the need for users to provision, manage, and scale their build servers. This convenience is because the service itself manages these tasks. Essential features of AWS CodeBuild encompass:

1. Managed Service: CodeBuild manages and scales the build servers, freeing users from server maintenance.
2. Continuous Integration: It integrates with the development and deployment workflow, automating the build and test phases of the software release process.
3. Package Production: After the build and test phases, it prepares the software packages, making them ready for deployment.

AWS CodeBuild seamlessly integrates with other AWS services, enhancing the CI/CD (Continuous Integration/Continuous Deployment) pipeline's efficiency and reliability.

Github/Gitlab/Bitbucket Credentials

Default source credentials

This is the legacy option where it's possible to configure some access (like a Github token or app) that will be shared across codebuild projects so all the projects can use this configured set of credentials.

The stored credentials (tokens, passwords...) are managed by codebuild and there isn't any public way to retrieve them from AWS APIs.

Custom source credential

Depending on the repository platform (Github, Gitlab and Bitbucket) different options are provided. But in general, any option that requires to store a token or a password will store it as a secret in the secrets manager.

This allows different codebuild projects to use different configured accesses to the providers instead of just using the configured default one.

Enumeration

# List external repo creds (such as github tokens)
## It doesn't return the token but just the ARN where it's located
aws codebuild list-source-credentials

# Projects
aws codebuild list-shared-projects
aws codebuild list-projects
aws codebuild batch-get-projects --names <project_name> # Check for creds in env vars

# Builds
aws codebuild list-builds
aws codebuild list-builds-for-project --project-name <p_name>
aws codebuild list-build-batches
aws codebuild list-build-batches-for-project --project-name <p_name>

# Reports
aws codebuild list-reports
aws codebuild describe-test-cases --report-arn <ARN>

Privesc

In the following page, you can check how to abuse codebuild permissions to escalate privileges:

AWS - Codebuild Privesc

Post Exploitation

AWS - CodeBuild Post Exploitation

Unauthenticated Access

AWS - CodeBuild Unauthenticated Access

References

• https://docs.aws.amazon.com/managedservices/latest/userguide/code-build.html