AWS - CodeBuild Post Exploitation

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CodeBuild

For more information, check:

AWS - Codebuild Enum

Check Secrets

If credentials have been set in Codebuild to connect to Github, Gitlab or Bitbucket in the form of personal tokens, passwords or OAuth token access, these credentials are going to be stored as secrets in the secret manager.
Therefore, if you have access to read the secret manager you will be able to get these secrets and pivot to the connected platform.

AWS - Secrets Manager Privesc

Abuse CodeBuild Repo Access

In order to configure CodeBuild, it will need access to the code repo that it's going to be using. Several platforms could be hosting this code:

The CodeBuild project must have access to the configured source provider, either via IAM role of with a github/bitbucket token or OAuth access.

An attacker with elevated permissions in over a CodeBuild could abuse this configured access to leak the code of the configured repo and others where the set creds have access.
In order to do this, an attacker would just need to change the repository URL to each repo the config credentials have access (note that the aws web will list all of them for you):

And change the Buildspec commands to exfiltrate each repo.

Leaking Access Tokens from AWS CodeBuild

You can leak access given in CodeBuild to platforms like Github. Check if any access to external platforms was given with:

aws codebuild list-source-credentials

AWS Codebuild - Token Leakage

codebuild:DeleteProject

An attacker could delete an entire CodeBuild project, causing loss of project configuration and impacting applications relying on the project.

aws codebuild delete-project --name <value>

Potential Impact: Loss of project configuration and service disruption for applications using the deleted project.

codebuild:TagResource , codebuild:UntagResource

An attacker could add, modify, or remove tags from CodeBuild resources, disrupting your organization's cost allocation, resource tracking, and access control policies based on tags.

aws codebuild tag-resource --resource-arn <value> --tags <value>
aws codebuild untag-resource --resource-arn <value> --tag-keys <value>

Potential Impact: Disruption of cost allocation, resource tracking, and tag-based access control policies.

codebuild:DeleteSourceCredentials

An attacker could delete source credentials for a Git repository, impacting the normal functioning of applications relying on the repository.

aws codebuild delete-source-credentials --arn <value>

Potential Impact: Disruption of normal functioning for applications relying on the affected repository due to the removal of source credentials.